Preheat the grill.

Slice peaches in half and remove the pits, brush the cut side with butter.

Place peaches cut side down on a piece of aluminum foil and cook over medium heat for 3-4 minutes. If you want grill marks, eliminate the aluminum foil, but watch them closely because the natural sugar in the peach easily burns..

Flip peaches over, sprinkle with cinnamon sugar and cook an additional 4-5 minutes.