Wash the meat briefly, dab dry with kitchen paper. Spread with 1 tablespoon of mustard. Clean and wash the leek, cut into length of the roulades and blanch for about 2 minutes. Drain the leek strips well and place them on the meat.
Put bacon on it. Roll up firmly from the tip. Tighten with roulade needles. Heat the oil in a casserole dish and fry the roulades in it thoroughly on all sides. Remove briefly and put aside.
Stir the rest of the mustard into the cooking stock and deglaze with red wine and stock. Add the roulades again and let them braise for about 3/4 of an hour at low heat with closed pot. In the meantime, clean the Brussels sprouts, wash them briefly and cook them for the last 15 minutes of braising time in little boiling salted water.
Remove the roulades and keep warm. Bring sauce to the boil, thicken lightly with sauce thickener. Bring to the boil again and season to taste with mustard, salt and pepper. Put the roulades back into the sauce. Drain the sprouts.
Swivel in fat. Wash the parsley, put something aside for garnishing. Chop the rest. Garnish roulades with chopped parsley and a small bunch of parsley. Add the Brussels sprouts. Serve with schmekken boiled potatoes.