Cut the fillet into pieces approx. 6 cm long and cut them in half lengthways. Season with pepper and wrap each with a slice of ham. Place the rolls in a baking dish. If you want, you can now distribute the drained mushrooms on top (if you use fresh mushrooms, the sauce could become a little too runny). Mix the cream with crème fraîche and sauce powder and pour over the meat. Sprinkle the grated cheese on top.
Place in the preheated oven for approx. 30 minutes at 180 ° convection or 200 ° top / bottom heat. If the surface gets too dark, cover with aluminum foil.