Preheat oven to 350 degrees F. Line an 8.5 x 4.5 loaf pan with parchment paper or spray with nonstick cooking spray.
In a medium bowl add the flour, baking soda, salt and cocoa powder. Whisk the ingredients together.
Add the bananas to a large bowl and mash them. Add the applesauce, maple syrup, milk, egg, and vanilla extract, and stir together.
Pour the dry ingredients into the wet ingredients and stir together with a rubber spatula.
Pour the batter into the loaf pan. Bake for 50-55 minutes or until a toothpick inserted in the middle comes out clean.