During the seudah ha’mafseket, one may eat an unlimited amount of raw foods, like fruits and vegetables. If one cooks them, however, they are considered a cooked dish, despite the fact that they are edible without cooking.
Cheese, yogurt, butter, and all other milk products that undergo pasteurization are not considered cooked, because they are boiled for health reasons, not in order to improve their taste (Sh.A. 552:4, Ba’er Heiteiv 5, K.H.Ch. 13).
If one cooks carrots and potatoes together, he may not eat both species [during the seudah ha’mafseket], because they are [considered] two cooked items. Rather, he should eat either of the two. Similarly, noodles cooked with cheese, or lentils cooked with eggs, constitute a mixture of two cooked foods and may not be eaten together. Even if one prepares two dishes using the same food item, the only difference being that one is made thin and the other thick, they are considered two cooked dishes. Similarly, hard-boiled and soft-boiled eggs are considered two dishes. However, a dish that is typically made by mixing two food items, one of which is the main ingredient while the other [merely] adds taste – like rice made with a touch of onions – is considered one dish (Sh.A. 552:3).
The prohibition applies to both cooked and fried foods, but baked goods – like bread and cake – are not forbidden, for their main purpose is to satiate a person (Eshel Avraham of Buchach). Some refrain from eating cake so as not to derive too much pleasure from the seudah ha’mafseket. Pizza is considered a cooked dish because of the cheese on top.
It is proper to refrain from eating chocolate, snacks, and sweets at the seudah ha’mafseket, because the entire purpose of these foods is self-gratification, not satiety (see Rama 552:1). However, if there is nothing else with which to satiate oneself, it is permissible to eat these items.
Some say that one should avoid pickled foods, like pickled cucumbers, so as not to derive too much pleasure from the seudah ha’mafseket. Besides which, they might be considered cooked foods (Sheyarei Knesset HaGedolah, K.H.Ch. 552:26). Others maintain that pickled foods are permissible (A.H.Sh. 552:7).
It is permissible to eat fresh salad seasoned will oil and spices at the seudah ha’mafseket. Some, however, recommend not eating fresh salad, so as not to derive too much pleasure from the seudah ha’mafseket(Chida, K.H.Ch. 552:11).
The [prevalent] custom is not to eat fish at the seudah ha’mafseket, because it is considered a distinguished food, similar to meat. Some are lenient when it comes to salt-herring and sardines, which were not previously cooked (see Sh.A. 552:2, K.H.Ch. 18).
Cooked beverages are not considered cooked dishes. Therefore, according to the letter of the law, one may drink beer, ale, coffee, and tea at the seudah ha’mafseket. However, many poskim rule that one should act strictly, le’chatchilah, and refrain from drinking these beverages, so as not to derive too much pleasure from this meal. One who drinks beer at every meal, and has difficulty digesting food without it, may drink beer at this meal as well. Coffee and tea are less important than alcoholic beverages; therefore, one who feels a need to drink them may do so. However, if one is easily able to do without them, it is preferable not to drink them. If it is necessary, one may drink sweet drinks, like cola, but one should not drink them just to indulge.
. See Rama 552:1; M.B. 4; Torat HaMo’adim 6:5, 6:10; Rav Karp’s [work] 6:6, 6:10.