I make several meals that have dehydrated meet in then and that takes a while to re hydrate.  I do not like spending the time at the stove to rehydrate so I bring my food to a boil and wrap it in a dish towel and put it in the bag that I keep my dishes in.  Then I go about my other camp chores.  By the time (maybe one hour) I get back to it will only be lukewarm. Usually it will take about 5 minutes to get it ready then.  I do not think my towel and bag is as good of an insulator as the cozy but it is with me already and it works good enough.