2 (16 oz.) cans French-style green beans, drained
1 can cream of mushroom soup
1 (4 1/2 oz.) jar mushrooms, drained
1 (8 oz.) can water chestnuts, sliced & drained
1 can French fried onion rings

Heat oven to 350 degrees. Mix green beans, soup, water chestnuts and mushrooms in casserole dish. Bake 15 minutes. Remove from oven and sprinkle top with onion rings. Bake 5 minutes longer.