Cut doughnuts in half horizontally; spread with butter. For each packet, place two doughnut halves cut side up on a 12-in. square of heavy-duty foil.
Sprinkle each with about 1 tablespoon brown sugar. Top with a pineapple slice; place a cherry in the center. Seal foil tightly. Grill over indirect medium heat for 2-4 minutes or until heated through. Yield: 10 servings.