Preheat oven to 350 degrees, and line a 9x5 bread pan with parchment paper, set aside.
In a small mixing bowl combine flour, baking soda and salt, mix together until combined. Set aside.
In a large mixing bowl, I used my KitchenAid mixer, mix together bananas and peanut butter until well combined and there are no visible banana chunks. Add in brown sugar and white sugar, stir until combined.
Add in eggs until well combined. Stir in milk, oil, and vanilla extract, stir until all the wet ingredients are incorporated. Slowly mix in flour mixture, until there are no clumps and mixture is smooth.
Divide batter in half by placing the second half of the batter in a separate bowl.
In a small bowl stir together melted chocolate and unsweetened cocoa powder. Pour this into the second bowl with half of the batter, mix the batter and chocolate until well combined.
Alternate between the two batters and pour into the prepared bread pan. I start with the plain, add chocolate, top with plain again, chocolate, then a tablespoon or two of the plain on top. Use a knife to swirl the batters, don’t over swirl, you will then combine the batters. Run the knife one time through the pan.
Place in oven and bake for 60-75 minutes, until center is completely cooked, toothpick or knife comes out clean when inserted in the top center of the loaf. Remove from oven and let cool for 10 minutes, then remove from pan, and let it cool completely before you serve.
Tip: If your bread appears to be browning too quickly, gently place a piece of foil over it like a tent, I did this with my loaf at the 45 minute mark.