Prepare or use leftover mashed potatoes
1-2 cans green beans, drained
1 lb. hamburger
Onion
Salt and pepper
1 can tomato soup or tomato sauce

Brown hamburger, onion, salt, and pepper. Place in bottom of casserole; drain and add green beans as next layer; top off with plenty of mashed potatoes, enough to cover casserole well. Dot with butter, salt, and pepper. Bake at 350-375 degrees to heat through and lightly brown potatoes.