Line two cupcake pans with liners. Preheat the oven to 350 degrees.
In a large bowl whisk together the melted butter, brown sugar, sugar, pineapple juice, egg, coconut milk, coconut extract and (optional) coconut rum. In a medium bowl, whisk together the flour, baking soda, baking powder and salt. Mix the dry ingredients into the wet.
Fill cupcake liners ⅔ of the way full. Bake for 20 minutes or until set and lightly golden. Allow to fully cool on a wire rack.
Add the butter for the frosting to the bowl of a stand mixer. Beat on medium speed for 3-5 minutes or until light and fluffy. Add the powdered sugar ½ cup at a time until fully mixed in.
Add in the vanilla and coconut extracts, coconut rum, salt and heavy cream and mix until the frosting thins enough to be piped. Add additional cream if it is too thick.
Transfer the frosting to a piping bag and pipe onto the cupcakes. Top with toasted coconut, pineapple tidbits and a cherry.