Preheat your oven to 350°F (175°C) and prepare a 9x5 inch loaf pan with cooking spray or butter.

In a large mixing bowl, combine melted unsalted butter and brown sugar, and cream together.

Add mashed bananas, eggs, and vanilla extract to the creamed mixture and blend until uniform.

In another bowl, whisk together flour, cocoa powder, baking soda, and sea salt, then fold into the wet ingredients.

Gently fold in semisweet chocolate chips if desired.

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

Bake in the preheated oven for about 60 minutes, checking for doneness with a toothpick.

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