Tuna Fish Casserole
["1/4 c. chopped onion", "1 Tbsp. butter", "1 can cream of mushroom soup", "1/2 c. milk", "1/2 c. shredded cheese", "1/2 tsp. dry mustard", "1 can drained tuna", "2 c. cooked macaroni", "1/2 c. peas", "1/2 c. potato chips"]
["In saucepan, cook onion in butter until tender.", "Blend in soup, milk, cheese and seasonings.", "Heat until cheese melts.", "Combine with tuna, macaroni and peas.", "Pour into a 1 1/2-quart casserole. Crumble potato chips on top.", "Bake at 350\u00b0 for 30 minutes."]
["onion", "butter", "cream of mushroom soup", "milk", "shredded cheese", "dry mustard", "tuna", "macaroni", "peas", "potato chips"]