Place steak in crockpot. Combine wine, soy sauce, garlic, broth,
catsup, mustard and onion; pour over steak. Cover and cook on low for 6 to
8 hours. Dissolve cornstarch in water; stir into pot. Add mushrooms.
Turn to high; cover and cook on high 20 to 30 minutes. From Crockery
Cookery by Mable Hoffman.