Clean and roughly dice the soup vegetables. Peel and halve the onion and roast the cut surfaces in a pan (because of the roasted aromas).
Bring a large saucepan with 2 liters of water and the salt to a boil. Put the prepared boiled beef with the bones, soup vegetables, onions and peppercorns in the water and cook with the lid closed at a low boil for about 2 hours.
Clean the spring onions and cut into very fine rings. Peel the tomatoes, cut in half, remove the seeds and cut into very small cubes. Chop the parsley and dill very finely.
For the marinade, mix together olive oil, vinegar, Tabasco, sugar and salt and season to taste. Add the spring onion, diced tomatoes, dill and parsley. Fill the whole thing up with enough cooled and well-seasoned beef broth that a homogeneous mass is created. Please do not keep it too watery.
Cut the cooled boiled beef into very fine slices. Either drape on a deep platter or place each individual portion on a plate and drizzle with the marinade. Sprinkle with freshly grated horseradish before serving.