Preheat the oven to 350°F (175°C). Grease a 9x5-inch loaf pan or line with parchment. Mash the bananas in a large bowl, then whisk in the melted butter, sugar, eggs, and vanilla until combined.

Add the flour, cocoa powder, baking soda, and salt directly to the wet mixture. Fold with a spatula just until no dry streaks remain; don’t overmix.

Fold in the ¾ cup chocolate chips, then scrape the batter into the prepared pan. Sprinkle extra chips on top and smooth the surface.

Bake on the middle rack for 55 to 65 minutes, until a toothpick inserted in the center comes out with a few moist crumbs. If the top browns too quickly, tent loosely with foil after 40 minutes.

Let cool in the pan 10 minutes, then lift out onto a wire rack to cool completely before slicing.