This is an old grilling recipe from Land O Lakes.
Meanwhile, combine all topping ingredients in 2-quart saucepan. Cook over medium heat until onions are softened (8 to 10 minutes). Remove from heat. Keep warm.
Shape ground beef into 4 (4-inch) patties. Place patties onto grill. Grill, turning once, until internal temperature reaches at least 160°F. or until meat is no longer pink in center (15 to 18 minutes).
To serve, place burgers onto bottom half of buns; top each with 2 slices cheese, 1 tablespoon onion topping mixture and top half of bun.