Cut off fish head, halve along the fish, take bones off.

Mix chopped cooked egg, ground pepper, salt and chopped greens, put the mass on one fillet, cover with the second fillet and tie with a thread.

Cook the fish in salted boiling water with vinegar, onion, peppercorns and bay leaf. Cool the fish in the stock. When serving, cut into portions.

Cream the cooked egg yolk with mustard, sugar and salt, adding oil step by step, then add vinegar. Mix with sliced cucumbers, mushrooms, sour cream and stir well up.