I was given a recipe years ago for what a lady called "make ahead potatoes".
It is mashed potatoes, with onion powder, cream cheese and sour cream. She told me to freeze them, and then, pull them out of the freezer when I was ready for them, cover with 1/4 cup of butter, paprika, and bake for an hour.
She explained that it was a perfect covered dish to take to church dinners, because she always had some in the freezer.
I personally have never had a batch of these potatoes last long enough to make it to the freezer, but I ate hers for years, at church dinners, and they were my favorite thing there.