I want to make a mushroom sauce (which includes onions) in a milchig, eino ben yomo pot. What is the halacha with the mushroom sauce? Can I consider it parve and eat it with chicken?
Answer:
The sauce should not be prepared in the milchig pot.
Sources: See Rema, Yoreh De'ah 95:2, who explains that onions fried in a meaty pot acquire the taste of the meat even in a pot that is not a ben yomo. Post factum, there are various discussions concerning leniencies, but it would certainly be prohibited to do so lechatchilah.