1 can cream of celery soup
1 c. milk
1 can (6 1/2 oz.) can water packed tuna, drained & flaked
1 c. uncooked elbow macaroni
1 c. frozen peas
1/2 c. chopped onion
1 c. grated Cheddar cheese (reserve 1/4 c.)

Whisk soup and milk in 2 quart microwave safe bowl until blended. Add remaining ingredients except 1/4 cup cheese. Cover and refrigerate overnight. Cover with lid or vented plastic wrap. Microwave on high 15-17 minutes until bubbly. Sprinkle with 1/4 cup cheese. Let stand 5 minutes until cheese melts.