Clean the mushrooms and shallots. Cut the mushrooms into thin slices and the shallots into small cubes. Wash the meat, pat dry with paper towels and cut into thin strips.
Sear the shredded meat in a greased hot roasting pan, then remove it and park it in between. Sweat the mushrooms and shallots in the frying fat. Stir in the mustard and pepper and let them form a roasting mixture. The roasted substances develop delicious flavors. Add the seared meat, cream and soy sauce and stir everything well. Cover and braise for about 30 minutes.
Arrange on the plates, sprinkle with the two types of cheese and bake under the preheated grill until the cheese has turned a golden yellow color.