10 3/4 oz. can cream of celery soup
1 c. milk
6 1/2 oz. can water pack tuna, drained and flaked
1 c. uncooked elbow macaroni
1 c. frozen peas (optional)
1/2 c. chopped onion
1 c. shredded cheddar cheese

Mix soup and milk in a microwave safe casserole until blended. Stir in remaining ingredients except 1/4 cup of the cheese. Cover and refrigerate at least 12 hours or overnight. Cover with lid or plastic wrap. Microwave on High 15 to 17 minutes or until bubbly. Sprinkle with reserved cheese. Let stand uncovered 5 to 7 minutes until cheese melts.