Preheat your oven to 375°F (190°C) and prepare a loaf pan by greasing it or lining it with baking paper.

Melt 5 tablespoons of butter in a small saucepan over low heat, then stir in 1 tablespoon of espresso powder until well combined.

Mash 4 ripe bananas in a mixing bowl until smooth with minimal lumps.

Combine the melted butter and espresso mixture with the mashed bananas until evenly mixed.

Mix in ½ cup of granulated sugar and 2 tablespoons of brown sugar until fully incorporated.

Crack 1 large egg into the mixture and stir until just combined.

In a separate bowl, sift together 1.5 cups of all-purpose flour, 1 teaspoon of baking soda, and 0.25 teaspoon of kosher salt.

Fold the dry ingredients into the banana mixture until just incorporated.

Fold in 3 ounces of grated semi-sweet chocolate until evenly distributed.

Pour the batter into the prepared loaf pan and smooth the top with a spatula.

Bake for approximately 40-50 minutes, checking with a toothpick in the center.

Cool the bread in the pan for 10 minutes, then transfer to a wire rack to cool completely.

Optionally, mix together the coffee butter ingredients until smooth to spread over warm slices before serving.