Slow Cooked Stroganoff

3 pounds boneless beef round steak
½ cup flour
1 ½ teaspoon salt
½ teaspoon ground mustard
1/8 teaspoon pepper
1 medium onion, sliced and separated into rings
2 cans (4 oz. each) mushroom stems and pieces, drained
1 can (10 ½ oz.) condensed beef broth undiluted
1 ½ cups (12 oz.) sour cream
Hot cooked noodles

Cut round steak into 3 x ½ inch strips. In a large resealable plastic bag, combine flour, salt, mustard and pepper. Add beef in batches; toss to coat.

In 5 quart crock pot, layer the onion, mushrooms and beef. Pour broth over all. Cover and cook on low for 8-10 hours or until meat is tender.

Just before serving, stir in the sour cream. Serve over noodles.