1. Mix ground beef, grilling sauce, garlic powder and salt in a large bowl until blended. Shape meat mixture into four 1/2-inch thick patties.
2. Preheat grill to medium-high heat. Grill patties to desired doneness topping with cheese for the last minute of grilling, about 8 minutes per side for medium.
3. Place burgers on bottom halves of buns. Top with lettuce, tomatoes and remaining bun tops. Serve with Irish Stout Mustard.