Clean or peel and wash the soup greens. Chop half. Peel onions. Cut 1 in half and roast in a large pot without fat. Boil up approx. 2 1⁄2 l water, vegetable pieces, laurel, peppercorns and approx. 3 tsp salt.
Wash the prime boiled beef. Cover and simmer for about 2 hours. Skim off any foam that develops more often.
Cut the rest of the soup vegetables into thin strips. For the Rösti, peel and wash the potatoes. Roughly grate the potatoes and 3 onions. Stir in egg and flour. Season with salt and pepper.
Heat 2 tablespoons of oil in a large frying pan. Flatten half the potato mixture in the pan and fry over medium heat for 6-7 minutes until brown. Place a sufficiently large flat lid on the pan to turn it over.
Press both against each other and turn them over with momentum. Melt 1 tablespoon of butter in the pan. Slide the light side of the Rösti back into the pan and fry for 6-7 minutes. Keep warm. Prepare a second Rösti in the same way.
In the meantime, lift out the boiled beef. Sieve broth and season to taste. Add strips of soup vegetables and boiled beef to the stock, cover and simmer for about 20 minutes.
For the salsa, wash the apple, quarter, core and finely dice it. Sprinkle with lemon juice immediately. Whip cream until half stiff. Stir in wasabi. Fold in apple. Season to taste with salt.
Wash parsley, shake dry and chop finely. Lift out the boiled beef. Serve with vegetables, some stock, apple salsa and rösti. Sprinkle with parsley.