Wash, peel and cut off the bottom 1 cm of each stalk of asparagus.  Cut ¼th of the asparagus into pieces.  Put the pieces and the peelings into a pot with 1 1/2 liters of water and cook for 15 minutes.  Strain the asparagus broth and set the liquid and the pieces aside.  In another pot melt the butter and add the flour to form a paste.  Using a whisk, slowly add the asparagus broth to the butter-flour paste and bring to a boil.  Add the cooked pieces of asparagus (not the peelings) to the liquid and blend everything using a stand mixer or blender.

Cut the remaining asparagus into pieces and add to the soup and cook another 15 minutes or until the asparagus is tender.  Finally in a small bowl, stir the egg with a container of sour cream (appr. 200 g).  Add a spoon of the soup to the mixture and stir.  Then add to the pot of soup.  Do not cook the soup any longer or the egg will curdle.  Season the soup with salt, pepper, nutmeg and lemon juice.  Garnish with chives or parsley and serve hot.