Preheat the oven to 180 degrees celsius
Grease all sides of a loaf tin with melted coconut oil
Make the chia egg by mixing the chia seeds with water, and leave to sit for 10 minutes
Make the buttermilk by mixing the plant milk and vinegar, and leave to sit for 10 minutes
Mash the bananas in a bowl, then mix in the chia egg and coconut oil (your oil should be melted but allowed to cool before mixing).
In a clean mixing bowl, mix all the dry ingredients together
Make a well in the dry ingredients bowl, pour the banana mixture in and combine well. If too dry, add in a dash of the buttermilk to help combine the dry and wet ingredients.
Transfer to a food processor with a whisk attachment. As you mix on medium power, pour in the rest of the buttermilk slowly until the consistency is thick but still liquid enough to fall off a spatula or spoon.
Use a spatula to scrape any mixture in from the sides, then continue to mix. You might not need to use all the buttermilk once you reach the desired consistency.
Transfer the mixture into the greased loaf tin and bake in the oven for 30-40 mins.
Remove from the oven, turn out of the tin, and allow to cool fully before glazing or serving.