Put rice in 600 ml boiling salted water and simmer covered for 10-15 minutes. In the meantime clean, wash and finely chop the spring onions. Peel and finely chop the onion. Wash tomatoes, dab dry and cut in half.
Clean lamb's lettuce, wash thoroughly and drain. Mix vinegar, onion cubes, some salt and pepper and finally add the olive oil. Mix the tomatoes into the vinaigrette and set aside.
Put rice in a bowl and first stir in parmesan and spring onions. Then add quark and eggs, also stir in and season with salt and pepper. Form 12-16 meatballs from the rice mixture.
Heat the oil in a large, coated pan and fry the meatballs until golden brown, turning them over. Arrange the lamb's lettuce on plates and spread the tomatoes with the vinaigrette on top. Serve with the hot meatballs.
Tomato ketchup tastes good with it.