Clean and wash the zucchini and eggplants. Cut the courgettes into thin slices. Wash and clean the tomatoes. Cut aubergines and tomatoes into approx. 1 cm thick slices. Peel onions and cut into thin rings.
Heat the oil in portions in a frying pan. First fry the aubergine slices in it, take them out and season with salt and pepper. Then fry the zucchini, also season with salt and pepper. Keep the zucchini and eggplant slices warm.
Fry onion rings in hot frying fat until transparent.
Wash the lemon, grate dry and finely grate half of the peel. Cut the lemon in half and squeeze one half. Mix quark, lemon juice and peel, except for a little bit for sprinkling. Season to taste with salt and pepper.
Lay vegetable slices in alternate layers of 8 turrets.
Wash the marjoram, shake dry and pluck leaves from the stalks. Spread the onions on the turrets. Garnish with marjoram. Arrange 2 turrets on plates. Add a dash of quark and sprinkle with lemon peel.