1 lb. hot or sweet Italian sausage links
1 med. onion, diced
1 (8 oz.) pkg. mushrooms, sliced
1 (15 oz.) jar melted spaghetti sauce
8 oz. pasta curls
1 (4 oz.) pkg. shredded Mozzarella cheese

Remove sausage from casings. Cook sausage and onion until sausage is browned, stir to break up sausage. Put sausage in medium bowl, in drippings cook mushrooms until tender. Return sausage to skillet, stir in spaghetti sauce and 1/2 cup water. Simmer, uncovered 20 minutes. Preheat oven to 450 degrees. Cook pasta as directed on label; drain. Stir pasta into sausage mixture, add half of the shredded cheese. Spoon into casserole, sprinkle with remaining cheese. Bake 15 minutes or until cheese melts.