Mix the oat flakes with the 5-grain flakes and the flaxseed in a bowl. Add enough water or milk to cover the whole thing. It is best to let it steep overnight in the refrigerator. If that gets too mushy for you, you can of course prepare the whole thing right before consumption.
Then add the chopped nuts and honey, rub in the apple with the skin, cut the banana into small pieces and mix the whole thing well. At the end, pour the yoghurt or quark over it and sprinkle with cinnamon if you like. Due to the sweetness of the honey, you actually don`t need sugar.
The muesli tastes delicious with all kinds of fruit (pear, berries, kiwi, grapes, mandarins etc.).