First, you either cut the apple into pieces or grate it, depending on your taste. Then crumble the cookie and add the oat flakes or muesli. If you like, you can add some sunflower seeds or other seeds. Finally, season to taste with milk or rice-soy drink.
Tip:
The muesli can also be supplemented with dried fruit. The recipe should serve more as a basic framework on which everyone can build their own composition.