MIX ground beef and Seasoning Mix until well blended. Shape into 4 patties.
GRILL over medium heat 4 to 6 minutes per side or until burgers are cooked through (internal temperature of 160ºF). Grill onion in grill basket or grill rack 3 minutes or until tender and lightly browned, stirring frequently. Add cheese slices to burgers 1 minute before cooking is completed. Toast rolls on the grill, open-side down, about 30 seconds or until golden.
SERVE burgers on toasted rolls with bacon and grilled onions.