Preheat oven to 350℉. Use muffin liners or spray the slots with olive oil.
In a large bowl, whisk together the bananas and eggs until mostly incorporated. Next, mix in the peanut butter and vanilla until combined. Then, add in your cacao powder, baking powder, salt, cinnamon and mix together until smooth. Fold in the chopped chocolate. Transfer batter to the muffin slots, filling 3/4 way up. Bake for 22-25 minutes or until toothpick comes out clean. Transfer muffins to a wire rack allowing them to cool completely.