1/4 c. chopped onions
1 tbsp. butter
1 can Campbell's cream of mushroom soup
1 (7 oz.) can tuna, drained and flaked
2 c. cooked elbow macaroni, about 4 oz. uncooked
1/2 c. milk
1/2 c. shredded processed cheese
1/8 tsp. dry mustard
1/2 c. cooked peas
1/2 c. potato chips (optional)

In saucepan, cook onions until tender in butter, blend in soup, milk, cheese and seasoning. Heat until cheese melts. Combine with tuna, macaroni and peas, pour into a 1 1/2 quart casserole. Crumble potato chips on top. Bake in moderate 350 degree oven about 30 minutes or until nicely browned and bubbling.