Preheat oven to 350°F. Spray or grease 1 loaf pan with the non-stick method of your choice.
In the bowl of an electric mixer combine mashed bananas, buttermilk, sugar, salt, vanilla, and espresso powder. Blend together until smooth. Add eggs one at a time and mix until completely blended.
In a medium-sized bowl, sift flours, baking powder, baking soda, and cocoa together.
Slowly add dry ingredients to the wet ingredients. Mix until just combined. Stir in chocolate chips and mix just until combined.
Pour into the prepared bread pan. Bake 40-45 minutes or until a toothpick inserted comes out clean.
Remove from pan and allow to cool on a cooling rack for 5 minutes and then remove muffins from pan to prevent continued cooking.
To make your own buttermilk you can add vinegar or lemon juice to milk. To make 1/2 cup buttermilk combine 1/2 cup of milk with 1/2 tablespoon of vinegar or lemon juice. Let it sit 5 to 10 minutes and then add to your recipe.*I like to add salt to the liquid ingredients. It blends and you are less likely to get a salty bite in your finished baked goods.
This recipe was calculated using the exact brands and measurements I used to make this recipe. If you are following a strict diet please note changing anything will cause the nutritional info to change. My calculations are intended as a guide only.