Preheat the oven to 350°F (180°C) and spray a 9x5 loaf pan with non-stick spray and line the bottom with parchment paper. Set aside.
Sift all purpose flour and cocoa powder into a mixing bowl and add white granulated sugar, light brown sugar, baking soda and salt. Mix together.
Add butter to a microwave safe bowl and microwave until melted.
Mash the bananas and measure them properly.
Then add the mashed banana, eggs and vanilla extract to the melted butter and mash everything together until well mixed.
Add the wet ingredients to the dry and mix into a thick batter. Don't over-mix.
Add the chocolate chips and fold them in.
Transfer to your prepared 9x5 loaf pan and smooth down. Add a few more chocolate chips directly to the top of the bread.
Bake at 350°F for 60 minutes. If it's showing any signs of over-browning you can bring it out at the 40 minute mark and tent it with foil, and then put it back in for the final 20 minutes.
Check for doneness by inserting a toothpick into the center of the banana bread. It should come out clean or with melted chocolate (no wet batter).
Let it cool in the loaf pan for a few minutes and then transfer to a wire cooling rack to cool completely before slicing and serving.