Preheat your oven to 180°C/350°F. Grease your loaf tin with oil and line with parchment paper.

Prepare flax egg by adding 2 tbsp water to 1 tbsp of ground flax.

Add lemon juice or vinegar to milk and stir. This is your 'buttermilk'. Leave to the side until needed later.

In a large bowl combine all dry ingredients together: flour, ground hazelnuts, baking powder, baking soda, salt, and cinnamon.

Mash bananas in a separate bowl until no large lumps remain. To the bananas combine brown sugar, vanilla, melted coconut oil, flax egg, and buttermilk, whisking until homogeneous.

Pour wet mixture into the dry mixture; stir to combine. Once the batter is almost fully mixed, add in chocolate chips and continue stirring.

Pour batter into prepared tin and place into preheated oven for 45 - 50 minutes.

Once the bread is out of the oven, leave to cool in the tin for 10 minutes then remove from its tin and parchment to continue cooling on a wire rack.