Preheat oven to 350 degrees F.
Line an 8x5-inch or 9x5-inch loaf pan with parchment paper in a way so it has handles to lift the bread later. Lightly grease it using baking spray or a little butter.
Mash bananas in a small bowl and set aside.
In a medium bowl, whisk together dry ingredients: flour, cocoa powder, baking soda, and salt. Set aside.
In a large bowl, beat together butter, brown sugar and vanilla.
Add in the egg and beat until well incorporated. Next, mix in sour cream, espresso powder, and ground ginger. Stop to scrape the sides and bottom of the bowl.
Add dry ingredients to the wet ingredients and combine. Add mashed bananas and stir to combine just until incorporated.
Lastly, stir in chocolate chips using a spatula. Do not over-mix.
Transfer batter into the prepared loaf pan and add more chocolate chips on top.
Bake 45-50 minutes or until a skewer inserted in the center comes out mostly clean. Transfer to a wire rack to cool for 10 minutes in the loaf pan, after which, lift the bread using the paper handles and place on a cooling rack to cook further.
Slice and enjoy!