Clean or peel the soup greens, rinse and roughly dice half of them. Halve an onion, but do not peel it off and roast it on the cut surface in a non-stick pan without adding any fat. Then take it out.
Put the beef leg slices in boiling water for about 3 minutes. Then take it out, rinse and pour off the water. Then put the beef leg slices in a large saucepan with 3 liters of cold water, simmer for 30 minutes and skim off the foam that is created. Then add the roughly diced soup greens, the roasted onion halves, 2 teaspoons of salt, bay leaves, juniper berries and the black peppercorns and let everything simmer for about 3 hours.
Cut the remaining soup greens into small pieces. Remove the beef leg slices from the soup and strain the soup through a fine sieve and then pour it back into the pot. Remove the meat from the bone and cut into bite-sized cubes. Add to the broth with the finely chopped soup greens and the Maultaschen and simmer for another 15 minutes. Season to taste with a little salt.
Rinse the parsley, shake dry and finely chop the leaves.
Peel the remaining two onions and cut into thin rings. Heat the sunflower oil in a pan and roast the onion rings until golden brown. Add to the stew with the chopped parsley.