Preheat the oven to 180*C (350*F) and spray an oven-safe bowl with cooking spray.
Make your protein shake by mixing water and protein powder in a shaker cup and set aside.
Mash the banana in a small bowl. Add baking powder and oats and mix. Pour protein shake into the bowl and mix everything until it is well combined.
Pour the oat mixture into the prepared oven-safe bowl and add a small teaspoon of Biscoff spread in the middle. Cover the Biscoff spread with oat mixture to create a gooey middle.