I am Sephardic. Is there any way in which it would be permissible to have a pot of food on the plata covered with a towel on Shabbat? Such as transferring the food to a pot in which it was not cooked, putting a towel just over the lid, and then putting it on the plata? Or this would also be asor? Thanks to the Rav
Sefardim should ideally be stringent, Some Sefardic Authorities are lenient to put a towel on top of the pot [as you describe], only on Friday for the purpose of the day meal.
The opinion of the Shulchan Aruch seems to be stringent in this matter. Transferring to another pot will not help as the pot is being returned to a heat source, making it hatmana bmosif hevel – insulation which adds heat and forbidden even with partial insulation according to the Shulchan Aruch 253:1. However, Or Ltzion, Tshuvot 2:17:10, is lenient as described above. This is because partial insulation is a dispute, in addition an outside heat source [hot plate] is also a dispute if it is considered “heat adding insulation” or not. When being done by night for the day meal, an additional leniency is added. WIth all three factors he is lenient and notes that the Sefardic custom is such as well.