For the dumplings, clean and wash the spinach and blanch it in salted water. Quench, squeeze well and chop finely.
Put the quark in a colander and drain well. Peel and dice the garlic. Mix the quark with the garlic, spinach, cheese, egg and breadcrumbs. Season with the lemon zest, salt and pepper.
For the tomato sauce, briefly blanch the tomatoes, rinse in cold water, peel and quarter them, remove the stalks and seeds. Then pass the seeds through a sieve. Put the resulting tomato juice aside and cut the pulp into small cubes.
Peel the onion and chop finely.
Heat the oil in a saucepan and sweat the onion in it until translucent. Add tomato cubes with tomato juice, season with salt and pepper and simmer over a low heat for 15 minutes. Finally sprinkle with parsley and keep warm.
A little tip: add a small teaspoon of sugar, that gives it a little more flavor.
With 2 tablespoons moistened in cold water, form oval cams from the spinach and quark mixture and let simmer in boiling salted water for about 8-10 minutes until they float on the surface. Lift out the cams with a slotted spoon and drain well.
Arrange the tomato sauce in plates and place the spinach quark dumplings on top. Serve sprinkled with a little cheese if you like.