Preheat your oven to 350°F (175°C) and prepare a greased 9x5-inch loaf pan.

Whisk together all-purpose flour, cocoa powder, baking soda, kosher salt, and espresso powder in a bowl.

In another bowl, mix olive oil, brown sugar, and granulated sugar until smooth and creamy.

Add eggs one at a time, mixing well; then add vanilla extract, sour cream, and mashed bananas.

Combine wet and dry ingredients gently with a spatula until just mixed, avoiding over-mixing.

Toss chocolate chips in a tablespoon of flour and fold into the batter evenly.

Pour the batter into the loaf pan, reserving some chocolate chips and optional banana slices on top.

Bake for 55-65 minutes, checking with a toothpick for doneness.

Let cool in the pan for 20 minutes before transferring to a wire rack to cool completely before slicing.