Preheat your oven to 170°C or 340°F and line a 9x5 loaf tin with parchment paper. Leave some overhang to make it easier to pull out of the tin once it’s baked.
Mash the bananas on a flat plate with a fork and set aside.
Give the walnuts a rough chop and set aside as well.
Whisk together the flour, baking soda, cinnamon, nutmeg and salt.
Then whisk together the oil, sugar, chickpea flour, water and vanilla extract until no lumps of chickpea flour remain. Add the mashed bananas and finish whisking.
Add the flour mixture and when it’s almost all incorporated, fold in the walnuts. Be careful not to overmix. It may cause you to have a gummy banana bread.
Pour the batter into the loaf tin and sprinkle the top with turbinado/coarse sugar.
Bake for 60 to 80 minutes or until a toothpick inserted in the center comes out clean. Let it cool around 10 minutes in the tin before removing and placing on a wire rack.