1 1/2 lbs. ground beef,
3 tbsp. finely chopped onion,
1/2 tsp. garlic salt,
1/4 tsp. pepper,
4 slices Cheddar cheese,
2 (5 oz.) jars sliced mushrooms, drained.
1/4 c. mayonnaise.

Directions:

In medium bowl, combine all burger ingredients; mix well. Shape mixture into patties using BurgerMate. In small bowl, combine all topping ingredients; mix well. Refrigerate until ready to barbecue. Grill hamburgers to desired doneness, turning once. During last several minutes of cooking, spoon about 1/4 cup topping on each burger. Continue grilling until cheese is melted. 6 servings.