In a large bowl combine ground beef, salt, and pepper. In a small, microwave-safe bowl heat 2 tablespoons peanut butter for 20 to 30 seconds or until melted. Add melted peanut butter to meat mixture; mix well. Shape into four 3/4-inch-thick patties.
For a charcoal grill, cook patties on the rack of an uncovered grill directly over medium coals for 14 to 18 minutes or until done (160 degrees F to 165 degrees F), turning once halfway through grilling. (For a gas grill, preheat grill. Reduce heat to medium. Place patties on grill rack over heat. Cover; grill as above.)
Remove burgers from grill. Spread toasted buns with remaining peanut butter. Place patties on buns and top with bacon. If desired, add additional Toppings.