• Preheat the oven to 350°F / 176°C. Lightly grease the loaf pan (9"x 5") with softened butter & flour or coat with flour cooking spray. (optional: line the inside of the pan with parchment paper).
• Smash the ripe bananas using a fork or potato masher. Add brown sugar, eggs, vanilla extract and mix. Add melted butter (cool) and mix.
• In a bowl: add flour, salt & baking soda while mixing everything together. (I highly recommend sifting the dry ingredients before adding to the wet ingredients, this will make the batter fluffy and not lumpy). Combine wet and dry ingredients together. Mix until well combined.
• Divide the batter into 2 bowls. Add cocoa powder into one bowl and mix (highly recommend sifting before adding). 
• Use an ice cream scooper or ladle. Scoop plain batter and chocolate batter alternately into a checkerboard pattern into the pan. Use a toothpick or butter knife to make the swirls in the batter.
• Bake for 55-65 minutes or until a toothpick placed in the center of the bread comes out clean. Remove from the oven and rest the bread in the pan for 15 minutes before transferring the loaf to a baking rack to finish cooling.

Slice, serve & enjoy!