Creamy Celery Soup

METHOD

• 1
  Cut the celery into 2 cm cubes. Finely chop the onion. Cut the potatoes into 1 cm cubes.
• 2
  Thoroughly wash the lemon and peel strips of zest from it – do not grate! Be careful, use only the yellow zest without the white pith, which is bitter. Squeeze the juice from half of the lemon.
• 3
  In a saucepan over medium heat, melt the butter, add the celery and onion, and sauté for 3–4 minutes. Stir frequently. Add 200 ml of cream and lemon zest and bring to a boil. Add the broth, potatoes, vinegar, lemon juice, sugar, a teaspoon of salt, and freshly ground pepper. Bring to a boil again, reduce heat to one-third, and cook for 20 minutes or until the potatoes and celery are tender.
• 4
  Remove the soup from the heat, take out the lemon zest, and blend the soup. Return to the stove and bring to a boil again.
• 5
  In a bowl, whisk the remaining cream with the egg yolks. Remove the soup from the heat and stir in the whisked egg yolks with cream. Season with salt to taste. Do not cook the soup any longer.