Preheat an outdoor grill or cast-iron grill pan to medium-high heat (approximately 400°F/200°C).

In a small bowl, whisk together the melted butter, brown sugar, honey, cinnamon, and salt until the sugar is largely dissolved and the mixture is emulsified.

Lightly oil the grill grates using a neutral high-smoke-point oil.

Brush both sides of each pineapple ring generously with the prepared glaze.

Place the pineapple slices onto the grill and cook for 3 to 5 minutes per side until distinct grill marks appear and the sugars have caramelized.

Remove the pineapple from the heat and serve immediately, optionally garnished with fresh mint.