Combine sour cream, mushroom soup, second 1/4 cup of melted margarine, and 1/4 cup chopped onion. Mix well. Put in remaining ingredients. Pour into greased 9x13 baking dish. Sprinkle top with corn flake mix and bake in 350° oven for 40-45 minutes until golden brown, and bubbly.
For a complete meal add 2-3 cups diced ham, chicken or sausage.