How to Make It
Shape beef into 4 patties.
Combine salt and next 4 ingredients; sprinkle evenly over both sides of patties.
Grill, covered with grill lid, over medium-high heat (350° to 400°) 5 minutes on each side or until beef is no longer pink.
Cook Caramelized Onions and vinegar in a saucepan over medium heat 5 minutes or until thoroughly heated. Spoon over burgers. Top with lettuce, and serve on rolls.