Boil the meat in salted water until tender. Strain the broth, and cut the meat into pieces.
Stew chopped onion, grated beets and tomato.
Put chopped potatoes, chopped cabbage and stewed onions with beets in the broth, lay the bay leaf and cook for 15 minutes.
Add mushrooms, kvass, salt and pepper to taste, cook until cooked.
Serve with sour cream and herbs.