Heat the olive oil, to high heat, in a large saucepan or flameproof casserole dish.
Add the lamb shanks and sear on all sides and remove, set aside.
Add the stock, juice, mustard, maple syrup and some salt and pepper to the saucepan and bring to a simmer. Return the lamb shanks, cover and simmer for approximately 2 hours, turning every half hour, until tender.
Serve with mashed or roast potatoes and wilted English spinach.