Mash the banana in a cereal bowl with a fork and mix with the yogurt. Stir in the muesli, cinnamon and berries and cover and leave to soak in the refrigerator overnight. The next morning, if necessary, sweeten with honey (the sweetness of the banana is enough for me), stir and enjoy.
Can also be taken with you to school / university or to work in a glass or a suitable can.