Preheat your oven to 350°F (175°C) and grease a loaf pan.
In a large bowl, mix mashed bananas, softened butter, sugar, eggs, and vanilla extract.
Dissolve espresso powder (or use brewed espresso) and add it to the wet mixture.
In another bowl, whisk together flour, baking soda, and salt.
Gradually add the dry ingredients to the wet mixture, stirring until combined.
Fold in the dark chocolate chips, ensuring they’re evenly distributed.
Pour the batter into the prepared loaf pan and smooth the top.
Bake for 50 minutes or until a toothpick inserted into the center comes out clean.
Allow the banana bread to cool in the pan for 10 minutes before transferring it to a wire rack.