1 (2 lb.) bag hash brown potatoes
1 lg. onion, chopped
1 c. sour cream
1 stick butter
1 lg. can mushroom pieces
1 can mushroom soup
1 c. Muenster cheese
1 c. American or Mozzarella cheese
2 c. crushed corn flakes

Fry onions and mushrooms in butter until golden brown. Add 1 can cream of mushroom soup to mixture. Stir until blended over low heat. In large bowl, put thawed potatoes and cheese, stir well. Pour mushroom soup mixture over potatoes and stir well until coated. Put potato mixture in a greased 9x13 inch dish. Sprinkle crushed cornflakes on top of potatoes before baking. Bake in 350 degree oven for 35 minutes.