01 -
Preheat the oven to 350°F (175°C). Prepare an 8.5 by 4.5-inch loaf pan by either buttering and flouring it or lining it with 2 pieces of parchment paper that hang over all 4 sides for easy removal.
02 -
In a medium bowl, whisk together the mashed banana, buttermilk, oil, egg, vanilla extract, and brown sugar until well combined.
03 -
In a large bowl, whisk together the flour, cocoa powder, baking soda, salt, and instant espresso powder, if using.
04 -
Pour the wet ingredients into the bowl of dry ingredients and stir just until combined, being careful not to overmix. Fold in 3/4 cup of the chocolate chips.
05 -
Pour the batter evenly into the prepared loaf pan and smooth out the top with a spatula.
06 -
Bake for 65 to 75 minutes, or until a toothpick inserted into the center comes out clean.
07 -
Immediately after removing the bread from the oven, sprinkle the remaining 1/4 cup of chocolate chips over the top. They will melt perfectly into the surface.
08 -
Allow the bread to cool completely before slicing and serving.