Mash the banana, the mix it with the cacao powder.
To make it look nice first layer half of the oats, milk and chia seeds then add a layer of the banana mix. Repeat. Finish off the oatmeal with a dollop of peanut butter.
Leave in the fridge overnight if possible, or at least 4 hours. When it comes to eating, give it all a good stir. Enjoy!