Cut one 12-by-16-inch rectangle each of foil and parchment. Arrange berries in the center of parchment and sprinkle with sugar. Crumple up in foil and cook, covered, on grill grates or coals, 5 to 7 minutes, until berries begin to burst. Top with granola.
Improvise with fixings like chopped dark chocolate, unsweetened coconut flakes, and frozen yogurt.