#1 Heat grill to medium heat #2 Mix first 4 ingredients just until blended #3 Shape into 8 (1/2-inch-thick) patties #4 Grill 5 to 6 min. on each side or until done (160F). Top with Singles grill 1 min. or until melted #5 Place lettuce, tomatoes and onions on bottom halves of buns cover with burgers, ketchup and tops of buns.