Preheat the grill to medium heat (about 375-400°F).
Whisk together melted butter, brown sugar, lime juice, chili powder, cinnamon, and kosher salt in a small bowl.
Brush the glaze mixture over the pineapple rings, reserving some glaze for later.
Grill the pineapple slices for 3 minutes on each side until caramelized.
Brush remaining glaze on the pineapple before serving.
Notes
This grilled pineapple is a versatile side dish that pairs well with BBQ, chicken, or as a sweet, healthy dessert. For added spice, sprinkle a touch of cayenne before grilling.