Saucy Sausage Shells

Cook macaroni shells according to package directions; drain. Rinse with cold water; drain again. Cook sausage in large skillet until brown, breaking up with wooden spoon. Drain off fat. Transfer drained sausage to large bowl; stir mushrooms into drained sausage. Stir in 1 cup of spaghetti sauce and half of mozzarella cheese. Heat oven to 350°F (175°C). Carefully stuff sausage mixture into macaroni shells. Arrange stuffed shells in 9x13-inch baking dish. Heat remaining spaghetti sauce in large saucepan until bubbly; pour evenly over stuffed shells. Sprinkle with remaining mozzarella cheese. Bake about 15 minutes or until cheese is melted.