Clean the livers and spray them with a little vinegar. Heat oil in a large pan and put the livers to be braised. When half done, add sliced onion crescents and mushrooms. Mix, add some salt and pepper to taste.
Once soft, top up with wine. Leave to evaporate for 2 minutes and add the sour cream (at room temperature). Stir and if needed, top the dish with a little water mixed into flour.
Add spices to taste and serve with chopped parsley. This is a tasty dish with other types of liver, too.