Prep the pan and oven: Heat oven to 350°F (175°C). Line a 9x5-inch loaf pan with parchment, leaving overhang for easy lifting. Lightly grease.

Mash the bananas: In a large bowl, mash bananas until mostly smooth with a few small lumps. You should have about 1 1/2 cups.

Whisk wet ingredients: Add eggs, oil, yogurt, sugars, and vanilla. Whisk until well combined and glossy.

Mix dry ingredients: In a separate bowl, whisk flour, cocoa, baking soda, baking powder, salt, and espresso powder if using.

Combine gently: Add dry ingredients to the wet mixture. Stir with a spatula until just combined. Do not overmix—a few small streaks are okay.

Fold in chocolate (and nuts): Stir in chocolate chips and nuts if using. The batter will be thick and creamy.

Fill the pan: Scrape the batter into the prepared loaf pan. Smooth the top and sprinkle a handful of chocolate chips over the surface.

Bake: Bake 55–70 minutes, until a toothpick inserted in the center comes out with a few moist crumbs but no wet batter. If the top is browning too quickly, tent with foil for the last 15 minutes.

Cool properly: Let the loaf cool in the pan for 15 minutes, then lift it out and transfer to a wire rack. Cool at least 1 hour before slicing for the cleanest cuts.

Slice and enjoy: Use a sharp serrated knife. For ultra-moist slices, wipe the blade between cuts.