I have a crock pot i use once a week for cholent. I want to cook hot cereal in it during the week using a plastic liner. I havent used the crock pot since shabbos. Can I pour milk into the cereal once it’s cooked and removed from the pot?
You may use the parve cereal with milk.
See Chochmas Adam 48:2 who is stringent in this case even though it is a Nat Bar Nat on an Aino Ben Yomo. The opinion of the Vilna Gaon Y:D 95 1-2 is that this is permitted, as is the opinion of the Ben Ish Chai [Korach, Year 2, siman 13]. While many are stringent when possible, in your case where you are using an additional layer between the food and pot, you can be lenient.