Peel the shallots and cut into wedges. Halve the chilli, remove the core and cut into fine strips.
Mix all ingredients well for the marinade. Brush the meat with it. Cover and let the meat marinate at room temperature for 4 hours. Then salt the meat.
Preheat the oven to 80 ° C. Put the wire rack in the lower half of the oven. Let the clarified butter get hot in a frying pan. Sear the meat in it over medium heat for approx. 10 minutes. Place the roast in the oven on the rack and cook for about 2 hours. Core temperature 60 ° C. The meat can then be kept warm in the oven at 60 ° C for 1 hour.
For the port wine sauce, simmer the shallots, chilli, port wine and balsamic vinegar in a pan over low heat for approx. 15 minutes. Stir in the cornstarch and simmer for another 2 minutes. Spice up.
Cut the meat open and serve with the side dish on preheated plates, pour the sauce over it. Serve. Serve a potato gratin or a risotto as a side dish.