Roast oat flakes without fat in a pan. Coarsely chop the pistachios. Wash apple, grate dry and quarter. Remove the core. Cut quarter into thin slices.
Put oat flakes, yoghurt and apple in a bowl. Sprinkle with pistachios. Wash the mint, dab dry and put the mint tip aside. Cut the leaves into fine strips and sprinkle over the muesli. Decorate muesli with mint