Put the dry ingredients (rice flour, tapioca flour, coconut flour, and baking soda + baking powder) in a big bowl and stir until there are no clumps.
Blend the wet ingredients (bananas, coconut milk, maple syrup, lime juice, vanilla extract, coconut oil) in a food processor or blender.
Add the wet ingredients into the dry ingredients and stir with a spatula until the mixture is just combined.
Split the batter into two bowls, so that you have about 1/3 of the batter in one bowl and 2/3 of the batter in the other bowl.
Add the ingredients for the chocolate layer (cocoa powder, coconut sugar, coconut milk, coconut oil) to the bowl with 1/3 of the batter and mix with a whisk.
Line a mold with parchment paper or grease it with a little bit of coconut oil. My mold measures 8 x 4 x 2.5 inches and preheat your oven to 390 degrees F (200 degrees C).
For the marble effect/swirl, just drizzle a tsp of light batter into your mold, then with a different spoon drizzle a tsp of the chocolate batter on top of it, then again the light batter, etc until no batter is left.
Bake in the oven for about 45-50 minutes (+/- 5 minutes). The cake is ready when a toothpick comes out almost clean (can still have some crumbs on it).
Enjoy your marbled banana bread with a chocolate spread!