Stuffed Steak

Cut a deep slit horizontally in steak to form a pocket and set aside. Heat butter or margarine in a large skillet. Add onion and mushrooms and cook until tender but not brown, about 5 minutes. Stir in ham, breadcrumbs, parsley, oil and pepper. Cook, stirring, 2 minutes. Fold cheese slice in half and place in meat pocket. Spoon stuffing into pocket and close with skewers or toothpicks. Place steak on a broiler pan and broil 3 to 4 inches from heat to desired doneness, turning once.