Wash the cured pork loin and pat dry. Place on a fat pan coated with oil and bake in a preheated oven (electric range: 200 °C/ gas: level 3) for about 1 hour. In the meantime, wash and drain the cherry tomatoes and carve them crosswise.
Heat the oil in a frying pan and briefly fry the cherry tomatoes in it. Remove. Season with salt and pepper and sprinkle with vinegar. Stir curd, sour cream and yoghurt until smooth. Season to taste with salt, pepper and lemon juice.
Wash the herbs, except the cress, dab dry and chop finely. Put something aside for garnishing. Add the remaining herbs to the quark mixture and puree finely with a hand blender. Peel and chop the onions.
Cut the cress from the bed, mix with the onions and remaining herbs. Slice the Kasseler thinly and arrange on a plate with some tomatoes. Sprinkle Kasseler with onion-herb mixture.
Garnish with basil and parsley. Serve sauce and remaining tomatoes separately.