Is a knish considered pas (bread)?
There are two ways to make knishes. Most home-made recipes for knishes involve folding meat or vegetables into a pocket of dough and then baking the knish. Because the dough is baked, this type of pastry is called pas haba’ah b’kisnin (bread with a filling), and is subject to the laws of pas palter (non-Jewish bread) and pas Yisroel (Jewish bread). Pas haba’ah b’kisnin is a form of bread that is usually served as dessert. As such, the bracha is normally borei minai mezonos, but if one is kovaya seuda (eats a substantial amount which constitutes a meal), the bracha is hamotzi.
However, there is another method which is commonly followed for retail knishes. Instead of baking the dough, the knish is deep fried in oil. Because the dough is fried in oil and not baked, halachically, this type of knish is not considered pas (bread). Even if one were to eat an entire meal of these knishes, they would require only mezonos, and not hamotzi. Therefore, these knishes are not included in the laws of pas palter/pas Yisroel, but rather the prohibition of bishul akum (foods cooked by a non-Jew without Jewish involvement) would apply. Bishul akum applies only to food that might be served at a fancy dinner. Since knishes are served at fancy dinners, the prohibition of bishul akum would apply. For this reason, all OU fried knishes are bishul Yisroel, with a Jew involved in the frying process.