Q. If cookie crumbs or graham cracker crumbs used as pie crust, are baked again when the pie is baked. does the second baking by a Yid make the crumbs pas Yisroel (bread that was baked by in a permitted way)?
A. Pas Yisroel is a stringency instituted in the times of the Mishnah to prevent assimilation due to the socializing that occurs when breaking bread together with Gentiles. Rema (Y. D. 112: 2) rules that Pas Palter or Pas Akum is in principle permitted even in situations where Pas Yisroel is available, however the custom of many is to be machmir.
Avnei Nezer (100) maintains that regarding the similar prohibition of Bishul Akum (food cooked by a Gentile), re-frying that cooked food or recooking food that was first fried, would render it permissible. He compares it to food that was not fully cooked, that becomes permitted if a Yisroel finishes the cooking.
However Poskim assert, that since in other issues we rule that there is no baking after baking, the above does not apply to our particular question. Besides, they argue that the prohibition of Pas Akum is in essence different than Bishul Akum. Since once the bread was baked by a Gentile it becomes similar to wine, and the prohibition cannot be removed by further fermentation. ((Binyan Av 36)
Poskim disagree if Pas Akum can become permitted by cooking it. Eitz Hachaim (Mahari Hagiz) opines that following the opinion of Shulchan Aruch (O.H. 318: 5) that there is cooking after baking regarding Shabbos, it will turn kosher. However, Maharil (Res. 165), assets that the Pas Akum prohibition cannot be removed by cooking the bread. (Shoel Venishal, introduction by Horav Ovadya Yosef zt’l, Sdei Chemed – Bishul).
Teshuvos Vehanhogos (1: 444) debates whether Pas Akum would become permitted by toasting it.
Horav Shlomo Miller’s Shlit’a opinion is that although Pas Akum is in principle a stringency, re-baking it will not make it permitted.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller Shlit’a