Preheat your oven to 350°F (175°C) and grease a standard loaf pan.

In a large mixing bowl, whisk together the all-purpose flour, cocoa powder, baking soda, kosher salt, and espresso powder.

In a stand mixer, combine olive oil and both sugars, beating until smooth and creamy. Add eggs one at a time, mixing well between additions.

Mix in vanilla extract, sour cream, and the mashed overripe bananas until blended.

Gently fold the dry ingredients into the wet mixture until combined, avoiding overmixing.

Toss dark and semi-sweet chocolate chips in flour, then gently fold into the batter.

Pour the batter into the prepared loaf pan and sprinkle with reserved chocolate chips and banana slices if desired.

Bake for 55–65 minutes or until a toothpick comes out clean. Cool in the pan for 20 minutes before transferring to a wire rack.