Preheat oven to 350°F (165°C). Line standard muffin tins with paper liners.

Place crushed pineapple in a sieve over a bowl to drain, reserving the liquid. Blend the coconut milk well to combine the separated fats and liquids.

In a small bowl, combine rum, ¾ cup (180 ml) coconut milk, ¼ cup (60 ml) of the reserved pineapple juice and vanilla. Set aside.

In a medium-sized bowl, whisk together the flour, baking soda and salt. Set aside.

In a large mixing bowl, beat butter and sugar until light and fluffy.

Add eggs to the butter-sugar mixture one at a time, beating well after each addition.

Alternately add the flour mixture and the rum mixture, half at a time, beating until combined.

Fold in the coconut and 1 cup (240 ml) of the drained pineapple.

Fill cupcake liners ¾ full with batter. Bake for 19-20 minutes, until a toothpick inserted in the middle of a cupcake comes out clean. Cool for 10 minutes in the pans on wire racks then remove cupcakes from the pans and cool completely.

For the frosting, blend the coconut milk well to combine the separated fats and liquids and set aside.

In a large mixing bowl, beat butter and vanilla until light and fluffy. Gradually beat in the powdered sugar.

Slowly beat in the coconut milk. Continue beating until fluffy.

To assemble cupcakes, place Coconut Buttercream Frosting into a pastry bag fitted with a large star tip (I use a Wilton 1M) and pipe a swirl of frosting onto each cupcake. Sprinkle with shredded coconut and decorate with paper umbrellas, if desired.