Peel the pineapple by slicing away the skin in vertical strips, then cut the fruit lengthwise into 8 long spears. Remove the tough core from each spear by making a diagonal cut along the center or using a thin knife to carve it out. Pat the spears dry with paper towels to remove excess moisture, which helps them caramelize better on the grill.

In a small saucepan over medium heat, melt the butter and add the brown sugar and cinnamon, stirring until the sugar dissolves completely and the mixture becomes smooth and fragrant, about 2-3 minutes. Remove from heat and stir in the lime juice and flaky sea salt. This butter sauce will be your basting glaze for grilling. I like to make this sauce just before firing up the grill so it stays warm and pourable.

Heat your grill to medium heat (around 375-400°F). Place the pineapple spears directly on the grill grates and brush generously with the cinnamon-butter sauce from Step 2. Grill for 10 minutes total, turning and brushing the spears with sauce every 2 minutes, ensuring all sides develop a caramelized golden-brown crust. The sugar in the butter sauce will caramelize beautifully and create a sweet, slightly charred exterior. I recommend using a silicone brush to apply the sauce so it doesn't burn on the grill grates.

Transfer the grilled pineapple spears to a serving plate and pour any remaining warm cinnamon-butter sauce from Step 2 generously over the top. Serve immediately while the pineapple is still warm and the sauce is flowing over the caramelized surface.