In your answer in https://dinonline.org/2012/01/05/covering-challah-on-pot/ my question is, can I put challah directly on top of a crock pot lid to warm it up on Shabbos? Or do I need to place something between the Challah and the crock pot lid? Thank you
As far as hilchos Shabbos, it is permitted to place the challah directly on the lid of the hot crock pot, coovering the challah is an issue of hatmana. The only consideration would be that you might be making the challah fleishig by putting it on the fleishig crock pot, therefore you might want to put something between them for this reason.