Peel and chop the onion. Peel, wash and chop the carrot, celery and potatoes.
Heat the oil in a large pot. Briefly sauté the onion, vegetables and potatoes. Pour on the stock, bring to the boil. Cover and cook for 20-25 minutes.
Cut the trout filets into pieces. Chives.
wash, dab dry and cut into fine rolls. Pour 200 g cream into the soup and puree everything briefly. Season to taste with salt, pepper, nutmeg and lemon juice.
Whip 100 g cream until semi-stiff. Arrange the potato soup in deep plates. Spread a blob of whipped cream on each plate in a spiral shape over the soup. Garnish with trout and caviar. Sprinkle chive rolls on top and serve immediately.