Preheat oven to 160°C.
Rub the lamb shank with olive oil, season with salt and pepper. Fry them in a large casserole dish until they change colour then put aside.
Add more olive oil to the pan and soften onion and garlic. Add all other ingredients, then put the lamb back and cook for 10-15 minutes, turning them regularly.
Put the lid on and place the dish in the middle of the oven. Cook for a couple of hours, turning the shanks every half hour and adding more stock if necessary.
The lamb is cooked when the meat is tender and it comes away from the bone easily.
Serve with lemon zest and chopped parsley scattered on top.