Ruth Schmidt's Hash

2 cups yellow onions, ground (or chopped very fine in a food processor)

4 cups raw Russet potatoes, peeled and ground (or chopped very fine in a food processor)

4 cups cooked leftover pot roast, ground (or chopped very fine in a food processor)

2 plus cups gravy (you can use a McCormick package or a can of beef gravy if you don't have enough.

Mix all ingredients together and bake in a large rectangular casserole at 400º for 2 1/2 to 3 hours.