In a large bowl, mix the softened butter and sugar well using a hand mixer.

Add the flour, baking soda, and baking powder to the butter and sugar mixture and mix until combined.

Add milk, oil, pineapple chunks, and 1/2 cup of shredded and toasted coconut to the batter.

Add coconut rum (optional) and mix evenly.

Preheat oven to 325 degrees F (160 degrees C) for 10 minutes.

Grease two 8-inch cake pans with butter.

Pour the cake batter into the prepared pans.

Bake in the preheated oven for 25 minutes, or until a toothpick inserted into the center comes out clean.

Remove the pans from the oven and let the cakes cool on a wire rack.

For the frosting, beat the softened butter until light and fluffy using a blender.

Add sugar and coconut milk to the butter and mix well until creamy.

Remove the cakes from the pans.

Place one cake on a plate and spread frosting all over the top.

Arrange pineapple slices and toasted coconut on top of the frosting.

Carefully place the second cake on top of the first.

Apply frosting over the top cake, covering both cakes completely.

Spread toasted coconut all over the cake.

Arrange remaining pineapple slices on top of the cake.

Refrigerate for at least 2 to 3 hours before serving.

Serve cold.