Prepare the Batter:

Preheat oven to 350°F (175°C). Grease a 9×5-inch loaf pan or line with parchment paper.

In a large bowl, whisk together mashed bananas, melted butter, and brown sugar until smooth.

Add eggs, vanilla extract, and espresso powder, mixing until well combined.

In a separate bowl, sift together flour, cocoa powder, baking soda, and salt.

Gradually add the dry ingredients to the banana mixture, alternating with sour cream, and mix until just combined.

Fold in chocolate chips.

Bake the Bread:

7. Pour the batter into the prepared loaf pan and spread evenly.

8. Bake for 50-60 minutes or until a toothpick inserted in the center comes out with a few moist crumbs.

9. Let cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.

Serve:

10. Slice and enjoy with a cup of coffee or warm with a spread of butter.