Cut the meat into 2.5 cm thick slices. Fry with fat in a pan, season with salt and pepper. Put in a greased baking dish.
Cut the mushrooms into slices and fry in the roasting fat, season, dust with flour and let brown. Add water and wine, heat while stirring, mix in cream and season with mustard and sauce. Pour over the meat, sprinkle with cheese and cook in the oven at 220 degrees for 15 minutes.