Heat The Bastard to a temperature of 220°C. immediately. Let the leg of lamb come to room temperature.
Chop the hard herbs (rosemary, thyme, oregano), clean and chop the garlic.
Coat the leg of lamb with the herbs and garlic and add salt and pepper to taste.
Tie up the leg of lamb with butcher's twine and grill it briefly in a direct flame (220°C) so that the outside is seared.
Wash the hay (if there is sand in it) and put it in the Dutch oven, pour in 2 cans of dark beer (in between, check if there is still enough liquid in it, add some extra beer if necessary), so that the hay is well wet. Reduce the temperature of the Bastard to 140°C. Put the Plate Setters on the Bastard, because you will cook the leg of lamb indirectly in the Dutch Oven. Place the briefly cooked leg of lamb on the hay and insert the thermometer, put the Dutch Oven on the Bastard with the lid on. Set the thermometer of the lamb at 52°C.
Place the potatoes on the Bastard with a plate setter underneath, for example on a cast iron plancha plate, and cook for about 35 minutes at 160°C.
Peel the asparagus twice all around and remove the bottom 2 cm. Grill these briefly (so that they get a grill strip) and add them to the Dutch oven about 15 minutes before your leg of lamb is ready so that they can finish cooking.
Remove the leg of lamb from the Dutch oven and let it rest for about 10 to 15 minutes before cutting it. (Remove the butcher's twine)
Smash the potatoes and spoon a dollop of sour cream on top and sprinkle with salt and pepper and some grated Parmigiano cheese and chopped parsley.
Cut the leg of lamb into nice slices as desired, place the Dutch asparagus against it on a board, together with the potatoes.