Heat the oil in a large saucepan, add the lamb and brown on one side, turn over and add the onion, carrot and swede and cook until both sides of the lamb are browned.
Sprinkle over the paprika, cook briefly then add the rice, dill and lamb stock. Spoon in the vinegar, sugar and plenty of salt and pepper then bring to the boil, stirring. Cover and simmer for 2½ hours until the lamb is very tender.
Lift the lamb out of the saucepan with a slotted spoon, transfer to a chopping board and cut the meat into small pieces, discarding the bones and fat. Return the lamb to the pan. Beat the eggs in a bowl, gradually mix in a ladleful of hot soup then pour into the saucepan. Heat gently until the soup has thickened slightly, but do not boil or the eggs will scramble. Taste and adjust the seasoning and vinegar if needed. Garnish with extra torn dill and ladle into bowls. Serve with sliced pumpernickel bread.