Put meat in salted water and bring to a boil. Cook the meat for about 30 minutes, removing the foam if desired.
Add the vegetables, reduce heat and simmer for another 30 minutes.
In the meantime, soak the rolls in milk until soft. Remove and squeeze dry, then mix with the marrow. Mix in egg, salt, pepper and parsley. Slowly add flour as needed to form a thick dumpling dough. Roll dough into roughly 40 smaller balls.
Mix the 4 tbsp spelt flour with a little water. Add to the soup and bring to a boil, stirring constantly. Season to taste with salt, pepper and parsley. Test consistency. If the soup is too thin, sauté additional spelt flour in butter and add to the soup. If too thick, add water.
When the soup is to your liking, add the dumplings and let simmer until they rise to the top.