Preheat the oven to 425°F. Spray two 12-count muffin pan with nonstick spray or line with cupcake liners. This recipe makes 14 muffins so one muffin pan will have two. Set aside.
Whisk together the flour, cocoa powder, baking soda, baking powder, and salt. Set aside.
In a large mixing bowl, mash the bananas using a fork, pastry cutter or potato masher— you want the bananas very well mashed. Whisk in the sugars, egg, applesauce, coocnut oil, peanut butter, and vanilla until combined. Using a rubber spatula or wooden spoon, stir in the dry ingredients. Stir until just combined and no flour pockets remain— be sure to not overmix. Fold in the chocolate chips.
Scoop the batter evenly into each cup or linger, filling each ¾ of the way to the top. Top with additional chocolate chips, if desired.
Bake the muffins for 5 minutes at 425°F then, keeping the muffins in the oven, reduce the oven temperature to 350°F. Bake for an additional 13-15 minutes or until a toothpick inserted into the center comes out clean. The total time for these muffins is about 20 minutes, give or take. Allow the muffins to cool for 5 minutes in the muffin pan, then transfer to a wire rack to finish cooling.
The muffins will stay fresh stored at room temperature for a few days– then transfer to the fridge for up to 5 days.