Preheat oven to 350℉. Grease and flour the loaf pan.
Combine the flour, baking powder, baking soda, and salt in one of the mixing bowls.
In the second mixing bowl, mash the bananas with a fork.
Add the rum, sugar, cinnamon, and cardamom to the bananas and stir to combine.
Add the melted coconut oil and chia seeds to the banana mixture and stir to combine.
Add the dry ingredients to the wet ingredients. Fold together until just combined with no large lumps.
Pour the mixture into the prepared loaf pan.
In the small bowl, combine the flaked coconut, sugar, and coconut oil with your fingertips to create a crumble. Sprinkle on top of the loaf.
Bake for about 50 minutes or until a toothpick inserted into the center comes out clean.