1 1/2 lbs. hamburger
1/2 onion, chopped
1/2 lb. sliced mushrooms
3-4 red potatoes, sliced (lg.)
1/2 c. mayonnaise
1 can cream of mushroom soup
3/4 c. sour cream
1 lb. grated cheddar cheese

Brown hamburger, onion, mushrooms; drain. In ungreased 9x13 pan line bottom with raw sliced potatoes. Spread hamburger mixture over potatoes. Mix soup, mayonnaise and sour cream and spread over hamburger mixture. Sprinkle with grated cheese. Bake at 350 degrees for 1 hour.