Peel the potatoes and cut into small cubes. Clean the celery, cut off the leaves and chop finely. Cut the sticks into small pieces.
Heat the oil, sauté the potato and celery stalk pieces in it (about 5 minutes), add some water (about 1/2 l) and simmer everything over a low to medium heat for a quarter of an hour. When everything is soft, puree with the hand blender. Then stir in the milk until creamy and let it warm up again (do not boil anymore!). Now add the cream horseradish. Season to taste with salt, pepper and finely grated nutmeg. Finally add the smoked salmon cut into fine strips (set aside for garnish). Garnish with the finely chopped celery leaves and a few strips of salmon.