Chicken noodle casserole recipe

Chicken second courses

½ cup chopped onion 3 tablespoons butter or 3 tablespoons margarine, melted 2 (10¾ ounce) cans cream of chicken soup 2 cups shredded cheddar cheese, divided 1 cup milk 3½ cups chopped cooked chicken 2½ cups cooked macaroni or any kind of pasta/noodles you prefer salt pepper ¼ cup Ritz cracker crumbs