2 c. cooked elbow mac
1 tbsp. butter
1 can cream of mushroom soup
1/3 c. water
1 c. cheddar cheese, shredded
1 tbsp. minced onion

Blend hot mac with butter in casserole. Blend together soup and water. Add to mac with 3/4 cup cheese and onion; mix well. Sprinkle remaining cheese on top. Bake at 350 degrees for 30 minutes or until heated through.