For the filling, chop the onion finely and fry until soft. Grind one fillet, add onion and chopped parsley to it. Salt and pepper to taste.
Beat off the fillet a little. Put the filling on it on one side. The number of fillets depends on the number of persons.
Roll the fillet in a roll starting from the side of the filling. Rewind so that when cooking the rolls do not break up.
Slightly fry the tartars in vegetable oil on all sides. Then add some water, spices to taste and simmer under the lid for 20 minutes. Remove the thread before serving.