Knead the minced beef with 2 tablespoons of butter, egg yolk, breadcrumbs and parsley to a smooth mass. Season with salt, pepper and nutmeg. Shape the meat dough into small dumplings.
Wash and peel the asparagus and cut off the woody ends. Cut into pieces approx. 3 cm long. Clean the mushrooms and cut them into slices. Clean and wash the soup greens and cut into strips. Clean, wash and cut the spring onions into rings.
Sweat the soup greens and spring onions in 3 tablespoons of melted butter. Pour in the broth and bring to the boil. Add the asparagus pieces. After about 10 minutes add the mushrooms and dumplings. Let simmer for about 5 minutes over low heat.
Finally stir in the creme fraiche. Serve the soup sprinkled with chervil.