Preheat oven to 350°F (175°C) and grease a loaf pan.
Mash bananas in a bowl until smooth and free of lumps.
Mix in melted butter, brown sugar, eggs, and vanilla extract until combined.
Sift together flour, cocoa powder, baking soda, and salt in another bowl.
Alternate adding dry ingredients and espresso into the banana mixture, stirring gently.
Fold in chocolate chips, because chocolate makes everything better.
Pour batter into the prepared loaf pan and smooth the top.
Bake for 50-55 minutes or until a toothpick inserted comes out with a few crumbs.
Let cool in the pan for 10 minutes, then transfer to a wire rack.
For the glaze, whisk powdered sugar, espresso, vanilla, and butter until smooth.
Drizzle generously over the cooled banana bread.
Slice and devour, preferably with a cup of coffee.