In a large skillet, brown meat; drain. Add tomato sauce, onions and green bell peppers; mix well. Cover; simmer for 5 minutes. Layer noodles, cheese, and meat mixture in a 1 1/2 quart casserole; cover. Bake @ 350 degrees for 40 minutes. Top with additional cheese, sliced, if desired. Makes 4 to 6 servings.