1/4 c. chopped onion
1 tbsp. butter
1 can cream of mushroom soup
1/2 c. milk
1/2 c. shredded processed cheese
1 (6 oz.) can tuna, drained and flaked
2 c. cooked elbow macaroni
1/2 c. cooked green peas
1/2 c. cracker crumbs

In saucepan cook onions in butter until tender. Blend in soup, milk, and cheese. Heat until cheese melts. Combine with tuna, macaroni, and peas. Pour into a 1 1/2-quart casserole. Crumble crumbs on top. Bake at 350 degrees for 30 minutes.