Separate the beef into 8 equal parts, flatten them out, and put a folded slice of American cheese in the middle of four of them.
Cover with the other four patties and pinch the ends.
Grill burgers over direct, medium-high heat, flipping once until desired doneness is reached, approximately 4 minutes each side for medium. Alternative: In a medium skillet over medium-high heat, sear the burgers 4 minutes on each side.
To finish the burger, place the patty and additional toppings on bun. Optional: Slice the burger buns and place on grill for 1-2 minutes to form grill marks.