Preparation Steps

• Heat the oven to 350°F and position a rack in the center. Lightly grease a 9×5-inch loaf pan, then line it with a parchment sling so the long sides overhang. Grease the parchment as well.
• Stir the espresso powder into the warm milk until dissolved; mix in the vanilla and set aside to bloom.
• In a large bowl, whisk together the flour, cocoa powder, granulated sugar, baking soda, baking powder, and fine sea salt until the cocoa lumps are broken up and everything looks evenly combined.
• In a separate bowl, mash the bananas until mostly smooth. Whisk in the eggs until the mixture is cohesive. While whisking, slowly stream in the oil and then the cooled melted butter to emulsify. Whisk in the milk-espresso-vanilla mixture.
• Make a well in the dry ingredients and pour in the banana mixture. Fold gently with a spatula until only a few flour streaks remain, then fold in 3/4 cup of the chocolate chips. Do not overmix.
• Let the batter rest for 10 minutes to hydrate the flour and cocoa (this improves moisture and the dome). Meanwhile, tap the pan on the counter to knock out any large air bubbles.
• Scrape the batter into the prepared pan and smooth the top. Sprinkle the remaining 1/4 cup chocolate chips over the surface and add a tiny pinch of flaky sea salt if using.
• Bake for 55–62 minutes, rotating the pan at the 40-minute mark. The bread is done when a tester inserted in the center comes out with a few moist crumbs but no wet batter. If the top is darkening early, tent loosely with foil for the final 10–15 minutes.
• Cool in the pan for 15 minutes, then lift out by the parchment and cool completely on a rack for at least 60 minutes before slicing.