Brown meat in butter; stir in tomato sauce.
Mix cottage cheese, cream cheese and sour cream; add green pepper and onion.
Make layer of noodles in buttered casserole.
Add layer of cheese mixture and then meat.
Dribble additional butter over top.
Turn into covered 2-quart casserole.
Bake in a 350-degree oven until bubbling, 30 to 45 minutes.