The meat is cleaned from the bones and cut into cubes.
Together with the bones boil it in a 5 liter (1 1/3 gallon) of with cold water, salt and peppercorns.
When the water starts to boil, skim the foam and simmer over low heat until the meat is cooked through and tender, then add the rice and cook for a further 10 minutes.
Remove the stems from the sorrel leaves, wash them well and chop them finely.
Add them to the soup and leave to boil for 2-3 minutes.
In a large bowl, prepare the cream. Take the soup pot off the heat and with a ladle add some of the soup to the sour cream in the bowl gradually, stirring with a whisk until the cream reaches about the same temperature as the soup.
Slowly stir it into the pot and simmer until thickened.
It can also be made with mutton, just clean the tallow, so that the soup is not too greasy.