Cut the ribs along the rib, pour 3 liters of cold water, bring to a boil, remove the foam. Add the parsley stalks and simmer for about an hour, until the meat is tender.
Add sausage cut into thick slices, carrots and, last but not least, potatoes. Cook for another 30-45 minutes. Transfer the meat and vegetables to a bowl, strain the broth.
Add kvass and bay leaf to the broth, season with salt and pepper to taste. Boil for 5-10 minutes. Mix sour cream with chopped garlic and horseradish, gradually add to the broth. Bring to a boil and immediately remove from heat.
Arrange the ribs, sausage, vegetables and half a boiled egg on plates. Fill with seasoned broth, sprinkle with finely chopped parsley.