In a bowl, combine shredded coconut with a pinch of salt and set aside.
In a large mixing bowl, sift together tapioca flour, rice flour, and arrowroot starch. Gradually mix in coconut cream, stirring for at least 10 minutes until smooth. Incorporate sugar until fully dissolved, then fold in mashed bananas. Finally, add coconut milk and a pinch of salt, mixing thoroughly.
Pour the batter into a square baking dish or individual aluminum cups, sprinkling the reserved coconut on top.
Set up a steamer by placing a large steamer basket in a pot filled with 1.5 inches of water, ensuring the water does not touch the bottom of the basket. Bring the water to a boil, then carefully place the baking dish or cups into the steamer. Cover and steam for 20 to 25 minutes, or until the cake is fully cooked.