01 - Preheat the oven to 350°F. Line a 12-cup muffin tin with cupcake liners.
02 - In a medium bowl, whisk together flour, baking powder, and salt. Set aside.
03 - In a large bowl, cream the butter and sugar together until light and fluffy, about 2-3 minutes.
04 - Beat in eggs, one at a time, then mix in coconut milk, pineapple juice, rum, and vanilla extract until combined.
05 - Gradually add the dry ingredients, mixing just until incorporated. Fold in the crushed pineapple and shredded coconut.
06 - Divide the batter evenly among the cupcake liners, filling each about 2/3 full.
07 - Bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean. Cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.
08 - Beat butter until creamy. Gradually add powdered sugar, then coconut milk, vanilla, and salt. Beat until light and fluffy.
09 - Frost the cooled cupcakes generously. Garnish with toasted coconut, a cherry, and a pineapple wedge, if desired.