Preheat the oven to 350F / 180C and line a large baking sheet with parchment paper or a baking mat.
In a large bowl, combine mashed bananas with peanut butter, optional maple syrup, and milk.
Sift in flour, protein powder, and baking powder. Stir in chocolate chips, and fold until combined.
The resulting "dough" should be slightly runny, like cake or pancake batter.
Scoop the mixture onto a lined baking tray. Tap the tray on the counter to let the cookie batter flatten, then bake for 15 minutes or until golden brown. Let cool and enjoy!