Beef Stroganoff - Crock Pot

3 lb. beef round steak, 1/2 inch thick
1/2 cup flour
2 tsp. salt
1/8 tsp. pepper
1/2 tsp. dry mustard
2 med. onions, thinly sliced and separated into rings
2 (4 oz. each) cans sliced mushrooms, drained or 1/2 lb. mushrooms, sliced
1 (10 1/2 oz.) can condensed beef broth
1/4 cup dry white wine (optional)
1 1/2 cups sour cream
1/4 cup flour

Trim all excess fat from steak and cut meat into 3 inch strips about 1/2 inch wide.

Combine 1/2 cup flour, the salt, pepper and dry mustard; toss with steak strips to coat thoroughly. Place coated steak strips in crock pot; stir in onion rings and mushrooms. Add beef broth and wine; stir well.

Cover and cook on low setting for 8-10 hours. Before serving, combine sour cream with 1/4 cup flour; stir into crock pot. Serve stroganoff over rice or noodles.