Baking Challah Close to Shabbat
Question
Answer
Hello
It is forbidden to bake anything close to Shabbat unless its "surface has crusted" before Shabbat, which is a degree of baking sufficient for eating under pressing circumstances.
Regarding other dishes, the degree is that it should be cooked "like the food of Ben Drosai" before Shabbat - meaning cooked to a degree that it can be eaten under pressing circumstances.
If it has not been prepared to this degree, it is forbidden to leave food or a dish - unless the fire is raked or covered, or other permissions apply.
In our times, for dishes - it suffices that the fire is covered with a metal sheet, or that it is placed on a hotplate.
In the oven - there are not so many effective permissions.
Moreover, opening an oven while it is operating poses the issue of turning the thermostat on and off.
Source
Shulchan Aruch, Orach Chaim, Siman 252-253