3 (10 oz.) pkgs. frozen mixed vegetables
1/4 c. mayonnaise
1 pkg. Kraft cheddar cheese, grated
1/2 c. chopped celery
1/2 c. chopped onion
1/2 sleeve Ritz crackers
1 stick butter

Cook celery and onion with vegetables according to directions. Drain off all water. Mix mayonnaise and grated cheese. Crush crackers, stir in melted butter. Sprinkle on top of casserole. Bake at 375 degrees for 20 minutes. Grease casserole dish.