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General Guidelines of Ikar and Tofel
The Bracha that one makes on the ikar (primary food) covers the Bracha on the Tofel (secondary food). This rule applies to Bracha Rishona and Bracha Achrona. 
Situations exhibiting an ikar ve’tafel relationship include both when:
Two entities are intermixed and eaten together
Two entities are eaten one after another deliberately so that one entity will completely serve the other. 
In certain cases, the two foods are not considered a mixture and two brochot are required. If so, one should separate the one which has the more important Bracha (see Order of Brochos and make the Bracha, then make the other Bracha and eat that food. 
Once the initial situation of the food was a mixture and the two were eaten together, even if some Tofel remains without the Ikar, no new Bracha is needed.  However, if one added more Tofel after the Ikar was finished a new Bracha is needed. 
If one eats the secondary item before eating the primary item some say that one should make a Bracha on the secondary item as usual. However, some say that since, nonetheless, it is only secondary in purpose the bracha is automatically Shehakol, therefore, one should avoid such a situation and make sure to eat the primary food before the secondary one. 
In general, objective significance is eclipsed by subjective purpose. That is the determination of ikar depends on each and every person subjectively. Therefore, eating cake to temper the bitterness of a shot of whiskey demotes the cake to a status of tafel, notwithstanding the objective significance of flour. 
Making the bracha achrona for the ikar exempts the tofel from its bracha achrona as long as one ate a kezayit of the ikar.
However, if one didn't eat a kezayit of the ikar and one did a kezayit of the tofel one should recite the bracha achrona on the tofel.
The tofel is exempt from its bracha achrona even if it is less significant bracha achrona.
Foods Made With One of the Five Grains
Foods made with the five grains are Mezonot since the five grains are objectively more significant than other foods. 
Secondary ingredient serves the primary ingredient
The first category is if the Tofel serves the Ikar and isn’t eaten for taste but rather it is eaten only to enable one to eat the Ikar.  This category includes where the Tofel is to remove a bitter taste, add color, add smell, or make the ingredients stick together. 
Even if the two food aren’t eaten together still the Ikar covers the Tofel. 
However, if also has intent to eat the Tofel because of it’s taste, then 2 Brachot are needed. 
For example, one who drank bitter liquor and wants to remove the bad taste by eating bread should make a Bracha on the liquor and no Bracha is needed for the bread.  However, since it’s difficult to determine whether one is eating the bread just in order to remove the bitter taste or also for the satiation in brings independently, one should avoid having bread or mezonot just to remove a bitter taste. 
If a person has bread with olive oil and the olive oil is considered ancillary the Bracha on the bread covers the olive oil. However, if one has a little bread with a lot of olive oil (which one is having in order to soothe one’s throat) which is one’s primary interest the Bracha on the olive oil (HaEtz) and it exempts the Bracha on the bread. 
If one eats pickles or olives in order to whet one’s apittite for a meal (that’s one is not having bread), the main food such as meat is Ikar and the olive and pickles are Tofel. To avoid a dispute, one should eat a little of the meat first in order that it cover the pickles or olives. 
One of the ingredients of licorice is flour, however, since the whole purpose of the flour is to make the ingredients stick, the Bracha is Shehakol. 
If one of the ingredients of chopped-meat is flour or bread crumbs, however, since the whole purpose of the flour is to make the ingredients stick or to increase the volume of the meat, the Bracha is Shehakol. 
Secondary ingredient enhances the primary ingredient
The second category is if the Tofel is eaten to add taste, yet, one is eating the mixture primarily to eat one of the two foods and that’s called the Ikar.  The primary food and the enhancer is determined according to each individual’s preference. 
The Ikar only covers the Tofel if the two are eaten together (in one spoonful, forkful, or handful). 
If also has intent to eat the Tofel because of it’s taste and it’s especially dear or important to oneself, then 2 Brachot are needed. 
If mezonot is used as an enhancer and the foods weren’t cooked together, then two Brachot are required. This only applies for mezonot of the five grains and not rice. 
For crackers with cheese, if one’s primary intent is to eat the cracker, the Bracha is mezonot. 
For crackers with fish, if one is eating the fish to enhance the cracker, then the Bracha is Mezonot, however, if one desires both, then two Brachot are required (mezonot and shehakol). 
Chocolate bars filled with wafer and hazelnut cream, such as Elite "Pesek Zman" the wafer is Ikar, so one makes a Mezonot, but there are those who claim that the chocolate is Ikar, making it Shehakol.
For noodle Kugel and pickles eaten together, only mezonot is necessary. 
Latka with apple sauce, the only Bracha needed is for the latka (either HaAdama or Shehakol depending on it’s consistency). 
For blintzes with sour cream, the only Bracha needed is for the blintzes. 
For rice cakes with a peanut butter spread, the only Bracha needed is for the rice cakes (which is HaAdama). 
If a doughnut was dipped in coffee, the Bracha on the solid covers the absorbed liquids. There’s a minority opinion that the mezonot also covers the coffee in the cup and so it’s preferable to cover the coffee with another Shehakol, however, if it’s difficult one may make Shehakol on the coffee in the cup. 
For knishes in the usual case where the dough is substantial, the Bracha is mezonot. 
Ice Cream in Cone
If one eats an ice-cream in a cone and one’s intent is only to eat the ice-cream and the cone is only used to hold the ice-cream, one should only make a Shehakol. However, in the usual case where one eats the cone also for a taste, two Brachot are required.  Some say that the bracha is just shehakol.
Many authorities hold that cheese cake is Mezonot in the usual case where the cheese and crust are baked together. However, some say that the bracha is Shehakol unless there’s a thick crust in which case the Bracha is Mezonot. 
Fried chicken or fish (Shnetizel) with a thin batter coating is Shehakol, but if there’s a thick coating the Bracha is Mezonot, yet it's preferable to separate off a piece of coating and a piece of chicken and make Mezonot on the coating and Shehakol on the chicken. Some poskim however, hold that all types of shnitzel are mezonot. Lastly, some poskim consider all shnitzel shehakol. The Sephardic minhag is to make Mezonot if the batter is thick and Shehakol if it is thin. 
For onion rings in the usual case where the coating is substantial, the Bracha is mezonot. 
Bostom Creme Pie
For the bracha on Boston cream pies, if one has the filling as an enhancer of the cake then the bracha is Mezonot, however, if the filling is considered a thick layer for which one has intent to eat (not merely as an enhancer), then make two brachot, mezonot on the cake, and Shehakol on the filling. 
Both ingredients are equally important
The third category is where the Tofel is just as important as the Ikar in the eyes of the one who is eating it. In this case, the Ikar is judged by whichever is the majority unless one of them is Mezonot (five grains) in which case the Mezonot is automatically the Ikar. 
If the two items weren’t cooked together and one’s primary intent is for both items, each food requires a separate Bracha. For example, for an ice cream sandwich, two brochot are required. 
The Ikar only covers the Tofel if the two are eaten together (in one spoonful, or forkful). However, once the initial situation of the food was a mixture and the two were eaten together, even if some Tofel remains without the Ikar, no need Bracha is needed. 
Even if one has intent to eat the Tofel because it’s especially dear or important to oneself, still the Bracha on the Ikar covers the Tofel. 
For, pie or strudel with fruit filling which was baked together, one should only make Mezonot. 
The bracha on chulent (barley, beans, small pieces of meat, and potato) is Mezonot.
If there’s no barley, and the majority is potatoes and beans, the Bracha is HaAdama, if the majority is rice, the bracha is Mezonot.
If there’s no barley and the Chulent has the Bracha of HaAdama, if the kishka is eaten separately, it requires it’s own mezonot.
If the pieces of potato and meat are large enough that they aren't eaten together with the whole combination on each forkful, each component requires it’s own Bracha. 
If one mixes carrot, peas, and couscous/farfel the Bracha is Mezonot since the mezonot is always considered Ikar. 
The bracha on rice and meat chunks mixed up depends on the majority even though the meat is more expensive and important.
For an ice cream sandwich, 2 brochot are required (mezonot and shehakol) in the usual case where one’s intent is both for the ice cream and for the cookie.  Some say it is just mezonot.
For chocolate cream pie, if one eats it as a regular pie and the cream enhances dough, then only Mezonot is needed. However, if one is just as much for the cream as for the pie, then two Brachot (Mezonot and Shehakol) are required. 
For “Crembo” which is an Israeli candy that has a significant amount of cream on a biscuit and requires two brochot (Mezonot and Shehakol) in the usual case where the where the biscuit only adds some taste. In this case one should separate the biscuit make a Bracha on it, and then make a Shehakol on the cream.  Sephardim hold that one should just recite Shehakol and that covers everything.
For cereal and milk, the only Bracha required is for the cereal in the usual case where one has the milk to enhance the cereal. However, if one adds milk because one is thirsty and one’s primary intent is for the cereal and also for the milk, then two brochot are needed. 
If there’s left over milk, no new Bracha is needed. However, if a significant amount of leftover milk after finishing the cereal and one drinks the milk in a cup, then a new Bracha is needed. 
Fruit cocktail is considered one mixture, if the majority is HaEtz fruits, then the Bracha is HaEtz, and if the majority is HaAdama fruit, the Bracha is HaAdama. 
Salad which is mixed up with vegetables has the bracha as the majority item. If the majority of the ingredients are haadama, the bracha is haadama and if the majority is haetz the bracha is haetz. 
For a fruit salad where the pieces are small enough that one spoonful includes more than one piece, is judged by majority. If there’s a majority of fruit that have the Bracha of HaEtz which is the usual case, the Bracha is HaEtz. However, if there’s a majority of fruits which are HaAdama (such as pineapple or strawberry), then the Bracha is HaAdama.  However, the pieces are large enough that only one comes on the spoon or fork at a time, then each fruit requires it’s own Bracha. 
Many poskim say sushi is mezonot since the rice is in the majority and is primary. If the fish is primary to you then you make two brachot, mezonot and shehakol, first mezonot on rice and then shehakol on the fish. Others hold that if the fish is primary and you don't want the rice then just recite shehakol and exempts the rice.
Chocolate Covered Nut
If there’s a mixture of multiple items where each food is recognizable and none of them are the majority independently, each requires a Bracha. 
Regarding chocolate covered fruit or nuts, if one primarily wants to eat the nut or fruit and the chocolate enhances it, the Bracha is that of the nut/fruit. Conversely, if one primarily one wants to eat chocolate and the nut/fruit enhances the chocolate, the Bracha is Shehakol. 
If both the nut and the chocolate are primary, then many poskim hold that one should make the Bracha on the majority ingredient, while some say to make two Brachot.
Chicken chow mein
Chicken chow mein which is only made with chicken and vegetables is Shehakol if the chicken is the majority and HaAdama if the vegetables are the majority. 
If chicken chow mein is made with chicken, vegetables, and noodles, if the noodles are mixed well with the other ingredients then the Bracha is Mezonot. However, if the noodles aren’t completely combined then the Bracha is Mezonot on the noodles and either HaAdama or Shehakol on the rest depending on the majority (see previous halacha). 
If chicken chow mein is made with chicken, vegetables, and rice then one should make the Bracha on the majority item and exempt the other ingredients; if rice is the majority, say Mezonot, if vegetables are the majority say HaAdama, and if chicken is the majority say Shehakol. 
Noodles, dumplings, or soup nuts
If there’s a small amount of noodles, kneidlach (dumplings), or soup nuts one makes two Brachot, Shehakol on the soup and Mezonot on the noodles. 
If there’s a significant amount of noodles, kneidlach (dumplings), or soup nuts, and one is interested just as much in the soup as one is interested in the soup nuts, noodles, or dumplings one should only make Mezonot and it exempts the soup. 
If one is eating the noodles, kneidlach (dumplings), or soup nuts just because they’re there one only says Shehakol. 
↑ S”A 212:1 based on Brachos 41b. See Kol Bo (n. 24) who is uncertain about this.
The Chazon Ish (27:9) explains that a tafel is never excused from a bracha rishona. Rather, the tafel is excused from its own typical bracha because it is subsumed under the ikar and, therefore, covered by the bracha recited on the ikar.
See Pri Megadim (Preface to Hilchos Birkas ha’Peiros note 11) where he develops a hierarchy of objective significance, including foods comprising a quantitative majority, the five grains, and flavoring agents.
↑ Tur and Shulchan Aruch (212:1). Aruch HaShulchan (212:1-2) discusses two scenarios of ikar ve’tafel: 1) Where the tafel forms one food unit with the ikar, as the two components are eaten in one spoonful. 2) Where the tafel is eaten deliberately subsequent, but proximate to the ikar.
Sh”t Maharach Or Zaruha 38 writes that if one eats fruit seeds as regular food for sustenance the Bracha is HaEtz, however, if it is eaten only in order to sweeten a drink which one has afterwards the Bracha is Shehakol. The proof is that bread which is kneaded with spices (Pas HaBah Bekisnin) which is normally eaten as a sweet (snack) is Mezonot and even that it’s not clear and perhaps one should make Shehakol.
Sh”t Trumat HaDeshen 1:31 writes that if one eats a food in order that one will be able to drink wine not on an empty stomach even though it’s secondary it requires a Bracha because the food is eaten before the wine. He then quotes the Or Zaruha who said that if one is eating the seeds before the drink one makes a Shehakol on the seeds and infers that if a secondary item is eaten before the primary food the Bracha would be Shehakol.
However, the Bet Yosef 212:1 argued on the Trumat saying that just because it is coming for the purpose of sweetening the drink the Bracha shouldn’t change draws proof from the Rosh who says that if one ate less than a Kezayit of shivat haminim one shouldn’t make boreh nefashot because the appropriate Bracha doesn’t change is one just eats less than a Kezayit. The Darkei Moshe 212:2 rejects the Bet Yosef explaining that having the secondary food first requires a Bracha because one may not enjoy this world without a Bracha but it doesn’t deserve it’s appropriate Bracha since the purpose is secondary, however, if one eats less than the requisite amount the Bracha doesn’t change because one’s purpose was normal eating. The Rama 212:1 rules like the Trumat HaDeshen who says that if one ate the secondary item first one should only make a Shehakol on it.
See Magen Avraham (212:4) who disagrees with the Rama and holds that the bracha of the ikar food should be recited on the tafel.
Mishna Brurah 212:10 and Beiur Halacha s.v. VeAyno quotes many achronim who disagree with the Rama. Mishna Brurah concludes that one should avoid this situation by eating the primary food first.
↑Rabbi Alexander Mandelbaum in Yeshurun v. 33 p. 583 writes that the Shulchan Aruch 212:1 holds that the determination of ikar and tofel depends on each person and can change over time. Igrot Moshe OC 4:43 and Rav Nevinsal 208:3 agree.
↑Mishna Brurah 212:5. The Mishnah in Brachos 44a rules that the bracha recited on an ikar excuses the need for an additional bracha on the tafel if the consumer had both in mind when reciting a bracha on the ikar. Thus, when bread is secondary to a salty dish, one recites a bracha only on the salty dish (Tosfos Brachos 44a s.v. be’Ochlei peiros and S”A 212:1). However, it is important to note that the Mishnah Brurah (212:5 s.v “ve’achar”) paskins that a bracha on the bread would be in order if one had an appetite for it as well. Furthermore, based on a Shlah, the Mishnah Brurah advises to avoid such a situation of using bread to temper the effects of the whiskey, as it is difficult to ascertain definitively that one has no appetite for the bread itself.
In a slightly similar vein, Rav Moshe Feinstein (Igros Moshe 4:43) paskins that for strudel (fruit-filled pastry), one who would enjoy the pastry alone can make a Mezonos on the pastry followed by a Ha’eitz on the fruit. Similarly, for ice-cream wafers, if one would enjoy the wafer alone, one can make a Mezonos followed by a Shehakol. Rav Moshe explains that many people enjoy the Mezonos part alone, thereby warranting a separate bracha for those who desire the Mezonos part. Similarly, for cereal and milk, a bracha is also recited upon the milk if one would enjoy it independently of the cereal and drink it separately. Comparably, Rav Moshe paskins that chicken soup with k’neidel warrants only a Mezonos unless the chicken soup will be eaten separately from the k’neidel.
↑Halacha Brurah 212:12 writes that a bracha achrona on the tofel exempts the ikar even if the bracha achrona on the ikar is more significant such as if the tofel requires a mein shalosh and the ikar only requires a boreh nefashot. Igrot Moshe 4:42 implies the same.
↑Brachos 36b states that anything containing any of the five grains deserves a Mezonos. Shulchan Aruch 208:2 codifies this gemara. Rambam (Hilchos Brachos 3:4-7) understands this principle to be a function of ikar ve’tafel. Accordingly, Tosfos (Brachos 36b s.v. kol she’yaish) write that the flour in a mixture warrants a Mezonos only when the flour serves to satiate, and not merely to hold the components together. While Tosfos do not mention explicitly that this principle is a function of ikar ve’tafel, the Rosh (Brachos 6:7) does, explaining that flour serving as a binder is not considered ikar. However, the Ritva (Brachos 47a s.v. ha’koseis) learns that the five grains are an exception to the typical rules of ikar ve’tafel, warranting a Mezonos even when not assuming the role of ikar in a food.
↑ VeTen Bracha (Halachos of Brochos by Rabbi Bodner, chapter 4, pg 59). See Rashi (Brachos 41a s.v. She’hayah Tz’non ikar) with regards to an olive eaten to temper the sharpness of a radish. See also Rashi (Brachos 41b s.v. Devarim ha’Ba’im) with regards to foods eaten in a meal to enhance bread.
↑ VeTen Bracha (Halachos of Brochos by Rabbi Bodner, chapter 4, pg 60, 74)
↑ Vezot HaBracha (pg 90, chapter 11), VeTen Bracha (Halachos of Brochos by Rabbi Bodner, chapter 4, pg 74)
↑ VeTen Bracha (Halachos of Brochos by Rabbi Bodner, chapter 4, pg 74) and Vezot HaBracha (pg 90, chapter 11) write that usually the fish is used to enhance the cracker and so only Mezonot is needed. However, they conclude, if one specifically desires the fish, then 2 Brachot (Mezonot and Shehakol) are required. Peni HaShulchan (pg 338; Rabbi Pinchas Vitman) writes that the usual case is where one primarily wants the fish and one should make 2 Brachot.
↑ Veten Bracha (Halachos of Brochos by Rabbi Pinchas Bodner, chapter 4, pg 69)
↑ Veten Bracha (Halachos of Brochos by Rabbi Pinchas Bodner, chapter 4, pg 79). Shulchan Halevi 3:14:6 p. 38 writes that knishes are mezonot if the crust is thick and filling thin which is commonly the case, however, if the dough is thin and filling thick then it requires two brachot.
↑ VeTen Bracha (Halachos of Brochos by Rabbi Bodner, chapter 4, pg 61), Vezot HaBracha (pg 390), Shulchan Halevi 3:14:3 p. 37. Igrot Moshe 4:43 writes that if someone enjoys the cone then he should make two brachot and if he just wants the ice cream and he is eating the cone because it is there then the bracha is shehakol and the cone is covered. This is based on the Mishna Brurah 168:45.
↑ Dirshu 168:35 cites Rav Wosner (Kovetz Mbet Levi v. 16 p. 81) and Or Letzion 2:14:20 who hold that the bracha on ice cream in a cone is shehakol since it is eaten together and the cone isn't the main thing.
In Gemara Brachot 36b, Rav and Shmuel say that anything which has (flour from) the five grains is mezonot. (This is known the rule of Kol SheYesh Bo.) This is quoted by the Rif (Brachot 26a), Rosh (Brachot 6:7), and Rambam (Brachot 3:4) and codified by Tur and Shulchan Aruch 208:2.
Tosfot 36b s.v. Kol writes that if the flour is added in order to fill one up then the food is Mezonot, whereas if it’s added as a binding agent it’s not mezonot. Moreover, the Rashba (Brachot 36b s.v. Duvsha) writes that if the flour is added in order to give a taste or make the food more fit for consumption the Bracha is Mezonot. This is quoted by the Bet Yosef 208:2 and codified as halacha by the Mishna Brurah 208:7. The Rambam (Brachot 3:6) writes that if the flour was added as a binding agent or only in order to impart a color or smell the food isn’t mezonot because of the flour.
Vezot HaBracha (chap 11, pg 92) writes that if the cheese layer is baked together with the crust layer the Bracha is Mezonot based on Kol SheYesh Bo.
Laws of Brachos (Rabbi Forst, chap 7, pg 219) writes in general the crust is used to add flavor and if so the Bracha is Mezonot, however if the crust is only meant to hold the cheese the Bracha is Shehakol. The OU agrees.
The second clause is based on the following: Shulchan Aruch 168:8 and 212:2 rules that if one eats jam/marmalade on a cracker one should only make a Bracha on the marmalade and it exempts the cracker. Mishna Brurah 168:45 explains that in the case of S”A one was only eating the jam on the cracker so as not to dirty one’s hands. Then, he quotes the Magen Avraham 212:5 who writes that nowadays the crackers have a good taste and one should make Mezonot and exempt the jam. Mishna Brurah concludes by saying that it’s only one Bracha when it is baked together, however, if they’re baked separately it would require two Brachot.
Laws of Brachos (chap 7, pg 219, note 48) writes his ruling that if the thin crust is added for it’s taste even if wouldn’t be eaten on it’s own, the Bracha should be mezonot is based on the Mishna Brurah 168:45 but feels that Rav Moshe in Igrot Moshe 4:43 would disagree and hold that if one wouldn’t want to eat the crust on its own the Bracha is only Shehakol.
Igrot Moshe 4:43 writes that for an ice cream sandwich one should make two Brachot, mezonot on the wafer and Shehakol on the ice cream and if one only wants the ice cream but only eats the wafer simply because it’s there the Bracha is Shehakol and it exempts the wafer. However, Laws of Brachos (chap 7, pg 217, note 40) argues that even if the crust is negligible the Bracha should be mezonot as long as it adds a taste.
Halachos of Brachos (chap 4, pg 79) writes that in many cases the crust is only used to enhance the appearance of the cake and so the Bracha is Shehakol, however, if there is a thick layer he quotes Rav Moshe who says that the Bracha is Mezonot.
Halachos of Brachos (Rabbi Bodner, chap 4, pg 79) quotes Rav Elyashiv that the Bracha would be Mezonot in all cases in opposition to Rav Moshe, Rav Yacov Kamenetsky, and Rav Sheinburg who said Shehakol if it was a thin crust. He also quotes Rav Moshe and Rav Sheinburg that if there's a thick coating that one should make Mezonot. In the Halachos of Brachos Handbook (pg 13 and 43) he rules like the second opinion that if there's a thin coating the bracha is Shehakol and if there's a thick coating the bracha is Mezonot.
VeZot HaBracha (chap 12, pg 109) agrees that if there's a thin crust one should make Shehakol, however, he argues that if there's a thick coating one should separate a piece of the coating and a piece of the meat and make Mezonot on the coating and Shehakol on the meat. [See Vezot HaBracha (Birur 19(1), pg 261) where he seems to agree that if there's a thick coating the bracha would be Mezonot but because of controversy he suggests separating the coating and making two brachot.]
↑Halachos of Brachos p. 79 quoting Rav Elyashiv. Laws of Brachos (Rabbi Forst, chap 218, pg 218) writes that it seems that the opinion who says that breaded cutlets are mezonot is correct, but one who wants to satisfy all opinions should make mezonot on a piece of crust and Shehakol on another food.
↑Peninei Halacha (Rabbi Melamed) writes that all Shnitzel is shehakol. Also, Piskei Teshuvot 208:6 cites the Shevet Halevi 4:161, 6:24, Lehorot Natan 4:9, Cheshev Haefod 3:72, and Beer Moshe 5:61 who say that all shnitzel is shehakol. Shevet Halevi explains that since it is only a crust it is by definition secondary.
↑Yalkut Yosef (Brachot (vol 3), pg 426) writes that the bracha is Shehakol whether it is home made chicken cutlets or restaurant cutlets (where the coating is thicker). Yet, Rav Yitzchak Yosef Motzei Shabbat Vayhakel Pekudei 5778 min 37 explained that one should recite mezonot on shnitzel nowadays. They used to be shehakol since they were made with a bit of crust but today they're made with a lot of breading and they are mezonot. There is no safek brachot lehakel here since either way one would exempt any food besides salt and water with a mezonot. Also, Halacha Brurah 208:12, Or Letzion 2:14:19, and Birkat Hashem v. 3 p. 336 all hold that if the coating is thick the bracha on Shnitzel is mezonot.
↑ Veten Bracha (Halachos of Brochos by Rabbi Pinchas Bodner, chapter 4, pg 79)
Shulchan Aruch 168:8 and 212:2 rules that if one eats jam/marmalade on a cracker one should only make a Bracha on the marmalade and it exempts the cracker. Magen Avraham 212:5 writes that one honey crackers are primary and one only makes a Bracha on that and it covers the marmalade.
Mishna Brurah 168:45 rules like the Magen Avraham but adds that it’s only one Bracha when it is baked together, however, if they’re baked separately it would require two Brachot, one for the cracker, one for the marmalade because one is not eaten as an enhancer of the other but rather one is eating it for both of the cracker and the jam. However, Mishna Brurah 212:6 rules that if one eats cheese on a cracker one only makes a Bracha on the cracker even if one likes the cheese because one is eating the cheese as a spread.
[It’s clear that the Mishna Brurah 212:6 is discussing where one didn’t bake it together, because if so, the Shaar HaTziyun 212:21 should have answered that the difference in cases between in 212:5 and 212:6 was that in 212:5 it wasn’t baked together and in 212:6 it was.] Similarly, Sh”t Shevet HaLevi 7:27(6) explains that Mishna Brurah 168:45 only meant to make two Brachot when there’s a thick layer of jam but if there’s a thin layer one should only make one Bracha.
To clarify this distinction: Vezot HaBracha (chap 11, pg 99) rules that if there’s a cake with a thick layer of whipped cream, cheese, or ice cream and the two were not baked together one should make two Brachot (similar to the case of Mishna Brurah 168:45). However, if one eats the cream or topping of fruit, chocolate, or nuts in order to enhance the cake one should only make a Bracha on the cake. [See Vezot HaBracha (Birur 42) where he explains the distinction at length.]
Boston crème pie is a cake and not a pie (like the name implies). It is made with two layers of sponge cake and is filled with a thick layer of custard or cream. Laws of Brachos (Rabbi Forst, pg 360, pg 385, note 9) explains that one should make two Brachot on Boston crème pie because the filling is not merely an enhancer of the cake (and is similar to Mishna Brurah 168:45). However, Halachos of Brachos Handbook (Rabbi Bodner, pg 15) explains that Boston crème pie is simply a cake and the filling only enhances the cake and so the Bracha should be Mezonot (similar to Mishna Brurah 212:6). OU also writes Mezonot.
↑ VeTen Bracha (Halachos of Brochos by Rabbi Bodner, chapter 4, pg 504, Handbook pg 70) writes that since the filling was baked together with the crust, they form one entity and deserves only one Bracha. This is also the opinion of Vezot HaBracha (Luach Brachot pg 394)
↑Vezot HaBracha (p. 94) citing Rav Shlomo Zalman. The fact that this is considered one mixture is based on the Aruch Hashulchan 212:2 that anything eaten together on the same fork or spoon is considered one mixture. However, Or Letzion 2:14:30 seems to disagree as he writes that the bracha on large pieces of meat and rice even though they are mixed up are two separate brachot.
↑ VeTen Bracha (Halachos of Brochos by Rabbi Pinchas Bodner, pg 72, chapter 4), Vezot HaBracha (pg 92, chapter 11).
↑ Shevet Halevi 7:27:6 writes that the bracha on an ice cream cake with ice cream between two layers of cake or a ice cream sandwich the bracha is mezonot. He explains that even the cake and the ice cream aren't cooked together and according to Mishna Brurah 168:45 one should make two brachot, this is different than the Mishna Brurah since here the ice cream is a filling for the sandwich or cake and not a topping. If the ice cream would be a thick layer on top of a mezonot then one should make two brachot but since the ice cream is just a filling and there's two layers of mezonot the bracha is mezonot on everything.
↑Veten Bracha (Halachos of Brochos by Rabbi Pinchas Bodner, Handbook pg 27)
↑Rabbi Alexander Mandelbaum in Yeshurun v. 33 p. 584 writes that since the rice and fish are one unit that are eaten in one bite it is considered a mixture that deserves only one bracha (Aruch Hashulchan 212:2). Even though the Mishna Brurah 168:45 disagrees if they weren't cooked together, Rabbi Mandelbaum quoted Rav Elyashiv who said that if the parts were thin and small such as in sushi it is called a mixture even according to the Mishna Brurah. Therefore, in his opinion, the sushi can only require one bracha, either mezonot or shehakol.
↑Mishna Brachot 44a establishes that the Bracha on the primary ingredient exempts the Bracha of the secondary one. S”A 212:1 codifies this. Mishna Brurah 212:1 writes that the secondary ingredient is the one which comes to serve or enhance the primary ingredient and if one likes both then the majority ingredient is primary. For example, Mishna Brurah 204:51 writes that sugar coated almonds are HaEtz even if the sugar is the majority because the sugar only enhances the nut. Therefore, Laws of Brachos (pg 215), Halachos of Brachos (pg 417), and Vezot HaBracha (pg 96) agree that if one primarily wants to eat the nut or fruit and one views the chocolate as enhancing the nut/fruit then the nut/fruit is ikar. Conversely, if one primarily one wants to eat the chocolate and the nut enhances the chocolate, then the chocolate is ikar.
↑If one likes both the nut/fruit and chocolate: (1) Rav Shlomo Zalman (quoted by Halachos of Brachos pg 417, note 61) and Rav Elyahsiv (quoted by Vezot 96) hold that one should make the Bracha on the majority ingredient and if that can’t be determined make Shehakol.
(2) Igrot Moshe 3:31 holds that one should make a Bracha on the chocolate and nut/fruit. If one has another fruit one should make HaEtz on that and Shehakol on the chocolate, otherwise make Shehakol on chocolate having in mind not to exempt the fruit and then HaEtz on the fruit. (3) Laws of Brachos (pg 215) writes that one should make HaEtz because HaEtz is really the proper Bracha on chocolate. However, on chocolate covered peanuts he agrees with Rav Moshe to make requires two Brachot. (4) See Yalkut Yosef (Klalei Sefer Brachot pg 208) who writes simply that chocolate covered nuts are the Bracha of the nut.
↑ Mishna Brurah 212:1 writes that a mixture of two foods neither of which is mezonot and one isn’t coming to enhance the other the Bracha depends on the majority. Vezot HaBracha (pg 90), Halachos of Brachos (pg 68), and Laws of Brachos (pg 214) agree. Therefore, Laws of Brachos (pg 362) writes that if there’s no noodles (or rice) in the chicken chow mein then it depends on the majority, if there’s a majority of vegetables the Bracha is HaAdama if the majority is chicken the Bracha is Shehakol.
↑Laws of Brachos (pg 362) writes if there are noodles in chicken chow mein the Bracha is Mezonot on the noodles, and Shehakol on the chow mein if it’s mostly chicken or HaAdama on the chow mein if it’s mostly vegetables. However, on pg 385 note 14 he qualifies that this is only the case when the noodles aren’t totally combines however if they are mixed in well then mezonot on the noodles exempts the other ingredients. Also, the OU writes simply that chow mein is mezonot. (Maybe they are assuming the noodles are mixed completely.)
↑Aruch HaShulchan 212:2 writes that for two different foods to be considered a single mixture they must be eaten together on a single spoonful. This is quoted by Laws of Brachos (pg 208), Halachos of Brachos (pg 64), and a similar statement is found in Vezot HaBracha (pg 91). Halachos of Brachos Handbook (Rabbi Bodner, pg 24) writes that chicken chow mein which is made with rice, chicken, and vegetables because it is usually eaten on the same forkful has one Bracha which depends on what is the majority, if it’s rice, the Bracha is Mezonot, if it’s chicken, Bracha is Shehakol, and if it’s vegetables the Bracha is HaAdama. [In general, Vezot HaBracha (pg 94) writes that if there’s no majority because there are three foods with different Brachot, then each food requires its own Bracha.]
↑ Laws of Brachos (pg 363) writes if there’s a small amount of noodles, kneidlach, or soup nuts one makes two Brachot, Shehakol on the soup and Mezonot on the noodles. Similarly, Halachos of Brochos (pg 72, chapter 4, Rabbi Pinchas Bodner) writes that soup nuts enhance the soup and so it requires two Brachot (Mezonot and Shehakol). Vezot HaBracha (pg 117, chapter 12) agrees and says that the same is true of noodles, or dumplings in soup. Vezot HaBracha specifies that this is usually the case when there is a small amount of noodles in the soup.
Vezot HaBracha (pg 117) writes that in order to avoid exempting the soup with the mezonot one should say the Shehakol before the Mezonot, while the Halachos of Brachos (pg 72) disagrees saying to make the mezonot first.
↑ Vezot HaBracha (pg 118, chapter 12) writes that if there’s a significant amount of soup nuts, noodles, or dumplings, and one is interested just as much in the soup as one is interested in the soup nuts, noodles, or dumplings one should only make Mezonot and it exempts the soup. Similarly, Laws of Brachos (pg 363) writes that if there’s a majority of noodles in the soup the Bracha is Mezonot.
↑ Vezot HaBracha (pg 117, chapter 12) writes that if one is eating the soup nuts, noodles, or dumplings just because they’re there, one should only make Shehakol on the soup and that exempts the noodles, kneidlach (dumplings), or soup nuts.
↑ VeTen Bracha (pg 73, chapter 4). See also Vezot HaBracha (pg 118#6, chapter 11)