For the marinade, first finely chop the herbs and garlic and mix. Season the whole thing with salt, pepper and cane sugar and use it to season the leg of lamb all over.
Peel the carrots, celeriac and onions and cut into pieces with the leek (only the white part). Put the vegetables in the Dutch Oven, place the leg of lamb on top and then pour red wine, lamb stock and tomatoes on top. Let the whole thing stew for about an hour and a half at about 180 degrees and then serve.