For the roast, sprinkle 1 kg of salt on a baking tray. Wash the meat and dab dry. Mix 1 tsp. salt, pepper and caraway seeds. Rub the roast up to the bottom and lay it on the salt bed. Roast in the preheated oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer) on the bottom rail for approx. 3 1⁄4 hours.
In the meantime, clean or peel, wash and chop the soup greens. Heat the oil in a large pot. Fry the bones thoroughly. Fry the vegetables briefly. Stir in tomato paste. Add peppercorns, cloves, pimento, 1 teaspoon salt, wine and 1 1⁄4 l water. Bring everything to the boil, cover and simmer for about 1 hour.
Pour the sauce stock through a sieve into a pot and bring to the boil. Mix the starch with some water until smooth and stir into the stock. Simmer for about 3 minutes while stirring. Season the sauce with salt, pepper and 1 pinch of sugar.
Take the roast out of the oven and let it rest for about 5 minutes. Lift from the salt bed and arrange. Serve with sauce.