Split open vanilla pod and scrape out the pulp. Add pod and pulp to saucepan with the brown sugar, lime juice, and salt.

Whisk together and place over medium high heat and bring to a boil, stirring just until the sugar has dissolved.

Remove from heat and let sit for at least 2 hours before using. Remove the vanilla pod. Once cool, place in a squeeze bottle or other sealable container.

Core pineapple, cut into eighths lengthwise.

Place pineapple on skewers, coat with syrup, and grill on high for 12 minutes (4 per side).