Several hours before cooking cut the kidney into two halves and put into large amount of cool water.
Change the water often. Then pour hot water onto it. Boil it several times, removing water, and pouring new hot water again.
Then wash the kidney in warm water and boil it together with meat, having poured cool water onto it. Chop the onion, carrots, and cucumbers.
Put them into a big pot, add oil, pour some stock, cover with a lid and simmer until ready (the ingredients must become soft).
Put the flour and tomato paste onto the frying pan and fry them together for a while.
Strain the stock and put it with the stewed ingredients (onions, carrots and cucumbers) into a pot.
Add potatoes cut into small pieces, the tomato paste fried with the flour, and the kidney and meat cut into pieces. Boil it.
The rozsolnyk is ready when potatoes get soft.
Put the chopped parsley and crushed garlic into it.
When serving put some sour cream into a plate.