Preheat the oven to 180 C. Grease and line a loaf tin with baking paper.Process the banana and feijoa pulp in a food processor until smooth (or mash with a fork). Add the melted coconut oil, maple syrup, egg and vanilla essence and process until combined.Sift together all the dry ingredients into a bowl and add the coconut sugar.Gently fold wet ingredients into the dry ingredients, add the walnuts and stir until just combined, don’t over mix.Pour into the prepared loaf tin and bake for 30-35 minutes, or until a skewer comes out clean.Leave to cool in the tin for 5 minutes before turning out onto a rack.