Chop the root vegetables into sticks (0.25 by 1.25 inches), pour the stock into a large pan and bring it to a boil. Add the vegetables, turn down the heat and let it simmer for 5 minutes.
Mix flour and whipping cream into the soup and bring it to a boil. Season to taste with sugar and vinegar. Then add lamb stock, and season to taste with salt.
Add fish and fish balls, and bring it to a boil. Turn down the heat and let it simmer for 7-8 minutes until it’s just barely cooked through.
Beat the egg yolks and sour cream. Serve on plates and stir in 2-3 tbsp. of the sour cream mix. Sprinkle chives over the soup.