Mix the meat, breadcrumbs, egg and season. Shape it into small dumplings and add to the simmering meat broth. Caution: the broth must not boil once the dumplings are in.
In the meantime, cook the rice.
When the meatballs are done, turn off the stove and discard about half of the meat stock. Season the rest of the broth with lemon juice, sour cream and spices as desired, add capers and serve everything with the rice.