Preheat the oven to 350℉ and spray or line an 8x8 pan (preferably metal).
In a large mixing bowl, add the mashed banana (or just mash the banana right in the bowl), eggs and maple syrup. Whisk vigorously for 30 seconds.
Add in vanilla and peanut butter and whisk until combined. Add in the almond flour and cocoa powder and whisk until combined. Add the chocolate chips and whisk again to combine.
Pour the batter into the prepared pan and spread evenly using a spatula. Bake for 18-22 minutes or until the centre is just set. A toothpick inserted in the centre should have some moist crumbs stuck to it. Don't overbake or you'll lose the fudgy texture.
Allow to fully cool and store in an airtight container for up to 4 days and enjoy!