1. Preheat the oven to 180C. Grease and line a loaf tin or dish.
2. Combine the dry ingredients by placing the flour, coconut sugar, baking powder, baking soda and salt together in a large mixing bowl. Mix the ingredients thoroughly with a whisk.
3. In a separate bowl, mash the bananas with a fork until smooth. Add the melted and cooled coconut oil, oat milk and vanilla extract into the mashed bananas and stir until well combined.
4. Make a well in the centre of the dry ingredient mixture then pour in the banana mixture. Using a spatula, fold the wet ingredients into the dry ingredients and mix it through thoroughly. Be careful not to over mix.
5. Remove a third of the mixture and place it in a separate bowl. Stir in the chocolate spread until fully combined. Using two separate spoons, add a tablespoon of each batter at a time into the loaf dish, alternating between the two. Once both batters have been used up, take a flat knife or skewer and swirl it through the loaf tin vertically creating a marbled effect.
6. Place the banana bread in the oven to bake for 1 hour, covering the top with tinfoil after 30 minutes. Check if the banana bread is done by placing a skewer through the centre, it should come out clean once it is completely baked through.
7. Remove from the oven and leave to cool on a wire baking rack for 1-2 hours, then chill in the fridge for one hour. The Chocolate Banana Bread tastes even better after sitting in the fridge for one day allowing the flavours to combine. Keep the banana bread in the fridge, stored in an airtight container and use within a week.