Preparation Prepare barbecue (medium-high heat). Combine ground chuck and salt in medium bowl. Shape into four 1/2-inch-thick patties. Place 1/4 of cheese in center of each patty. Using moistened hands, fold meat over cheese, enclosing completely. Shape meat into 3/4-inch-thick patties. Sprinkle cracked pepper on both sides. Stir together oil and garlic in small bowl. Brush both sides of bread and onion slices with garlic oil. Oil grill rack. Place burgers and onion slices on barbecue. Grill burgers to desired doneness, about 5 minutes per side for medium-rare. Grill onion slices until just tender, about 4 minutes per side. Grill garlic bread until golden, about 1 minute per side. Place 1 slice grilled bread on each of 4 plates. Top each with burger and onion slice.
Preparation Prepare barbecue (medium-high heat). Combine ground chuck and salt in medium bowl. Shape into four 1/2-inch-thick patties. Place 1/4 of cheese in center of each patty. Using moistened hands, fold meat over cheese, enclosing completely. Shape meat into 3/4-inch-thick patties. Sprinkle cracked pepper on both sides. Stir together oil and garlic in small bowl. Brush both sides of bread and onion slices with garlic oil. Oil grill rack. Place burgers and onion slices on barbecue. Grill burgers to desired doneness, about 5 minutes per side for medium-rare. Grill onion slices until just tender, about 4 minutes per side. Grill garlic bread until golden, about 1 minute per side. Place 1 slice grilled bread on each of 4 plates. Top each with burger and onion slice.