Peel the asparagus and cut into 3 cm long pieces. Cook in salted water with sugar for approx. 15 minutes, drain, collect the cooking water.
Melt the butter, stir in the flour, fill up with asparagus water and cream while stirring and simmer for 5 minutes. Stir in grated cheese. Season with chicken stock and nutmeg. Add the asparagus pieces.
Whisk the egg yolks with a little broth and stir into the soup - now do not bring to the boil.
Garnish the soup with smoked salmon strips and watercress before serving.