Remove center of bread to make a boat shape. Brown ground beef; add sauce, mushrooms and onion. Simmer 2-3 minutes. Pour into bread and top with slices of cheese. Heat on baking sheet at 350F for 10-15 minutes or until the cheese melts. Slice to serve. Serves 5-6.

Per serving: 565 Calories (kcal); 27g Total Fat; (43% calories from fat); 25g Protein; 55g Carbohydrate; 77mg Cholesterol; 1130mg Sodium Food Exchanges: 3 1/2 Grain(Starch); 2 Lean Meat; 1 1/2 Vegetable; 0 Fruit; 4 Fat; 0 Other Carbohydrates