Cut the meat into slices and brush with mustard. Heat the oil, fry the meat, then season with salt and pepper and remove from the pan. Wash and clean the vegetables.
Divide the broccoli into small florets and blanch in salted water for approx. 10 minutes. Dice the carrots, blanch for 8 minutes (you can always use the same water !!) Cut the leek into rings in 1/8 water with salt and braise for 5 minutes. Place the carrots, leek, meat and broccoli alternately next to each other in ovenproof buttered dish. Mix the crème fraîche, cream and cheese, season with salt and pepper and pour over the vegetables / meat. Bake at 200 degrees for about 25 minutes.