Preheat oven to 350° F. Line the length of a 9" x 5" loaf pan with enough parchment paper to provide handles.
Spread shredded coconut evenly on a baking sheet and toast for about 5 minutes or until golden, stirring once or twice. Set aside.
Make the oat flour. Blend the rolled oats in a food processor just before it reaches a powder-like texture. Place 4 tbsp of oat flour in a bowl and reserve for the crumble. Place the remaining oat flour in a bowl along with baking powder, cinnamon, salt, and toasted coconut. Set the oat flour mixture aside. No need to clean the food processor.
Begin the crumble. Stir together all of the crumble ingredients into a bowl and mix until small clumps are formed. Set aside.
Return to the loaf. Place bananas, coconut milk, honey, vanilla extract, and melted coconut oil into the food processor. Blend until well combined. Return the oat flour mixture to the food processor and blend until just combined. Pour batter into loaf pan and smooth top. Sprinkle crumble evenly over loaf mixture.
Bake for 1 hour and 10 minutes or until toothpick comes out clean. Leave to cool on a wire rack for 30 minutes.