Preheat oven to 350F. Grease and line with parchment paper a loaf pan.
In a large bowl mash the bananas very well until they resemble a purée.
Add in the eggs, maple syrup, vanilla and coconut oil. Whisk until well combined.
Whisk in the almond flour, buckwheat flour, salt, baking soda, baking powder, cinnamon and the chopped dark chocolate until the batter is smooth.
Bake for about 40-50 minutes or until a toothpick inserted into the center comes out clean.
Let cool in the pan for about 5 minutes. Transfer to a cooling rack, let cool and enjoy.