Oven Swiss Steak

1 (2 pounds) boneless round steak
¼ teaspoon pepper
1 medium onion, thinly sliced
1 (4 ounce) can mushroom stems and pieces, drained
1 (8 ounce) can tomato sauce
Hot cooked noodles

Preheat oven to 325 degrees. Trim fat off beef; cut into serving-size pieces. Place in a greased 9 x 13 pan. Sprinkle with pepper. Top with onion, mushrooms and tomato sauce. Cover and bake for 1 ¾ to 2 hours or until meat is tender. Serve over noodles.