Cut the meat into pieces about three centimeters thick. As in the modeling of clay, hands give each piece a round shape and tie around the perimeter of the culinary thread to fix this shape. The thread tightens the meat, and therefore during heat treatment, when excess liquid evaporates, the bonds between the fibers inside the meat will break less. Dry the pieces with paper towels. It is important that there is as little moisture as possible on the surface – this will allow a crust to form, which also contributes to the preservation of juiciness.
Heat the frying pan with vegetable oil and fry the pieces of meat in it on both sides and from the end too. Five minutes on one side and three minutes on the other. From the butt – to the minute.
Put the meat in the foil so that it recovers from the shock, and in the fat and oil remaining in the pan, fry the coarsely chopped onion, celery and carrots until golden brown. Tie bay leaves, thyme and parsley. Put pieces of meat on a baking sheet, salt and pepper them and sprinkle around roasted vegetables. Throw a bunch of spices on a baking sheet and put it in the oven, preheated to 180 degrees, for fifteen minutes.
During this time, you need to prepare the sauce. In a skillet, mix the broth with the port, bring to a boil, and boil for ten minutes until the excess alcohol evaporates, and the contents of the skillet do not increase by about a third. Reduce heat and whisk in mustard and cream sauce. Boil for another three minutes, then remove from the heat and whisk in chopped small cubes and frozen butter and chopped tarragon leaves.
Take the meat out of the oven, let it recover from the next shock for a few minutes and serve with sauce and chips, for example.