Preheat the oven to 350 degrees Fahrenheit and prepare a loaf pan with parchment paper.
In a large mixing bowl add the ripe bananas and mash them together with a fork or potato masher.
Add in the brown and white sugars and whisk together until combined.
Then add in the softened butter, add the eggs, vanilla and sour cream. Whisk all the wet ingredients into the mashed banana mixture until distributed.
Lastly, add in the dry ingredients at once or flour, cocoa powder, baking powder and salt. Use a rubber spatula to fold the dry into the wet until no flour streaks are left and a slightly thick batter is formed.
Pour in the chocolate chips and fold into the batter again.
Pour this batter into the prepared loaf pan. Top with extra chocolate chips if desired and place into the oven to bake for about 55 minutes to an hour.
Use a toothpick to test if the loaf is done. You will know they are done when the toothpick is inserted and it comes out with slightly moist crumbs.
Once done baking, let cool completely. Remove from the loaf pan and cut into slices. Serve and enjoy!