Preheat an outdoor grill for medium-high heat.

Place a 12x12-inch sheet of aluminum foil onto a work surface. Spoon brown sugar and butter onto the center of the foil. Arrange pineapple ring over brown sugar mixture and place cherry in the center. Top pineapple ring with inverted shortcake shell. Fold the foil around cake to form a packet.

Grill the packet sugar-side down on the preheated grill until sugar is caramelized and cake is heated through, about 12 minutes.