Clean, peel, wash and dice the potatoes.
Clean broccoli and divide into florets. Put potatoes in a pot with water and cook for 10 minutes, now add broccoli florets and cook for another 10 minutes. Drain the cooking water and save 1/4 l of it. Remove two broccoli florets from the pot for garnishing. Add the meat stock to the 1/4 l cooking water and pour back into the pot.
Using a blender, finely puree everything. Stir in the milk and season with salt, pepper and nutmeg. Mix the egg yolk with the cream, stir into the soup and heat briefly. The soup must not boil anymore, otherwise the egg yolk will flocculate. Cut the broccoli florets into slices and add to the soup as a garnish.