Put the yogurt and low-fat quark in a small bowl and stir until smooth. If you like it a little sweeter, add some honey at this point.
Cut the banana into thin slices and add to the yogurt. Mash with a fork and fold in. Then add about half of the cereal. Cut the apple into thin wedges. Fold in a few wedges directly, place the rest on top to garnish. Sprinkle with cinnamon and the rest of the muesli.
Tastes delicious and keeps you full for a long time.