Preheat your oven to 350F.
Take two bread pans and lightly grease them with butter. Add a strip of parchment paper (this lets the bread release from the pan a little more easily) lengthwise. Reserve.
In a large bowl, mash the bananas with a potato masher. Add the melted & cooled butter, sour cream, brown sugar, white sugar, and 1 egg. Mix thoroughly with a wooden spoon.
In a medium sized mixing bowl, combine the flour, salt, cinnamon, baking cocoa, baking powder and baking soda. Fork mix.
Add the dry ingredients to the large bowl with the wet mixture. Stir to just combine. Don't overmix this.
Next, add your chocolate chips and gently mix to incorporate.
Portion your banana bread batter evenly between the two prepared bread pans and smooth the top evenly with a rubber spatula or small offset palette knife.
Sprinkle the batter with turbinado sugar.
Bake for 50 minutes at 350F, or until a toothpick inserted into the middle of each loaf comes out cleanly.
Remove from the oven and set on a wire rack. Let the bread cool in the pan completely.