1. Slice peach in half, remove pit. Prepare grill for medium heat. Grill peach, cut sides down 3 to 4 minutes or until slightly charred. Let stand 10 minutes. Slice each half into 8 to 10 thin slices.
2. Spread half peanut butter on 1 side of 2 bread slices. Divide peach slices evenly among each sandwich and place over peanut butter. Top with remaining bread slices.
3. Spread outsides of both sandwiches with butter.
4. Grill sandwiches 2 to 3 minutes on each side or until golden. Cut in half, if desired.