1 can cream of celery soup
1 c. milk
1 can tuna
1 c. macaroni, uncooked
1 c. frozen peas
1/2 c. onion
1 c. Cheddar cheese, shredded (reserve 1/4 c.)

Whisk soup and milk until blended. Stir in remaining ingredients except 1/2 cup of cheese. Cover and refrigerate 12 hours or overnight. Microwave 15 to 17 minutes. Sprinkle with 1/4 cup cheese. Let stand until cheese melts, 5 to 7 minutes.