Spinach Casserole

SPINACH CASSEROLE
2 pkgs. frozen spinach pieces, thawed 
2 c. cooked noodles 
1 c. shredded cheese 
1 can cream of mushroom soup 
1/2 c. onion, chopped 
1/4 c. butter or margarine 
Combine all ingredients in Crockpot. Cover and cook 4-6 hours on low. Serves 8.