Skin 2 onions, halve and cut into fine cubes. In a large bowl, knead together with the minced meat, mustard, quark, parsley and the oat flakes to a mass. Season to taste with salt and pepper and form 16 small patties. Heat clarified butter in a pan and fry the planters in it.
Meanwhile, grate the zucchini finely. Peel the 3rd onion, halve and cut into fine cubes, dust about 2 teaspoons of sugar over it. Sweat them in hot clarified butter until they are translucent. Add the zucchini and fry for 2 minutes. Then stir in the cream cheese and a dash of milk. Season with a little salt and pepper.
Arrange 4 meatballs on each plate and place the zucchini vegetables in the middle. Possibly place a zucchini slice on top to garnish and serve.