How to Make It
Preheat grill or grill pan to medium-high.
Combine sugar, mint, and rind in a mini food processor; process until mint is finely ground (mixture should resemble damp green sand).
Arrange pineapple on grill grates coated with cooking spray; cook 3 to 4 minutes on each side or until well marked. Arrange pineapple on a platter; drizzle evenly with butter. Sprinkle with sugar mixture; let stand 2 minutes before serving.