Preheat oven to 375°F.

In a cast iron pan over medium-low, toast ½ cup coconut for 2 minutes until golden; set aside.

In a large pot over low heat, melt 2 tablespoon butter, then add diced pineapple (⅓-inch pieces) and stir.

After 2 minutes, add white rum; cook 4 minutes.

Stir in brown sugar, remaining coconut, lime juice, and nutmeg; simmer 10 minutes, then remove from heat.

In a bowl, whisk flour, sugar, baking powder, and salt. Gradually add half-and-half until smooth; mix in vanilla.

In the cast iron pan, melt 6 tablespoon butter, remove from heat, and ladle batter evenly over melted butter.

With a slotted spoon (to leave liquid in the pot), add pineapple mixture gently over batter.

Bake 40–45 minutes until golden and set.

Cool 20 minutes, then top with ice cream and toasted coconut before serving.