Mix flour, egg, 1/4 teaspoon salt, nutmeg and mineral water to a smooth, thick dough. Clean and puree the liver. Knead under the dough. Let dough rest for 1 hour. Bring salt water to the boil.
Gradually place a portion of the spaetzle dough on a moistened wooden board and scrape fine strips into the lightly boiling salt water with a long knife. Bring to the boil until the spaetzle rise. Remove with a skimmer and rinse briefly in a sieve under cold water. Drain. Heat 1 litre of water. Stir the beef paste into the water. Add the spaetzle and heat everything again. Season to taste with salt, pepper and sherry. Wash and finely chop the parsley.
Heat 1 litre of water. Stir the beef paste into the water. Add the spaetzle and heat everything again. Season to taste with salt, pepper and sherry. Wash and finely chop the parsley. Arrange liver spaetzle soup in preheated cups and sprinkle with parsley