Preheat oven to 350F or 180C. Grease a 9*5 loaf pan and keep aside.
Add the ripened bananas to a bowl. Mash them well. Now, add oil and melted butter to it. Using a whisk, mix well until combined.
To the above mixture, add egg, vanilla extract, brown sugar. Mix well until smooth.
In another bowl, add flour, baking soda, baking powder, salt, cocoa powder. Stir in the ingredients together.
Sift the dry ingredients into the bowl of wet ingredients.
Mix them together until well combined. Add 1/2 cup chocolate chips and walnuts . Give a gentle mix. Make sure you don't over mix the ingredients.
Pour the batter into the greased pan. Top with remaining chocolate chips.
Bake for 50-55 mins or until done.
Remove the pan from the oven and set on a wire cooling rack. Let the bread cool in the pan for 15 minutes. Run
Run a knife around the edges of the bread and gently remove from the pan. Let the bread cool on the cooling rack until it comes to room temperature. Cut into slices and serve.