How to Make It
In a small bowl, combine the cumin, coriander, curry powder, rosemary, thyme, garlic and pepper. Stir in 6 tablespoons of the olive oil to make a paste and season it generously with salt. Place the lamb shanks in a large roasting pan and rub them with the spice paste. Cover with plastic wrap and refrigerate overnight.
Return the lamb to room temperature. Scrape off most of the spice paste from the shanks. In a large skillet, heat 1 tablespoon of the olive oil until shimmering. Add half of the lamb shanks and cook over moderately high heat until browned all over, about 10 minutes; transfer the shanks to a plate. Wipe out the skillet. Lower the heat to moderate and repeat with the remaining tablespoon of olive oil and lamb.
Preheat the oven to 350°. Add the celery, onion and carrot to the skillet and cook over moderate heat until barely softened, about 5 minutes. Add the wine and bring to a boil. Add the stock and bring to a boil. Wash the roasting pan and return the browned shanks to it. Pour the vegetable mixture over the shanks, cover with foil and roast for about 3 1/2 hours, or until the lamb is very tender. Lower the oven temperature to 200°. Carefully transfer the shanks to a baking dish and cover tightly with foil; keep warm in the oven.
Strain the sauce into a medium saucepan. Skim off as much fat as possible. Boil the sauce over high heat until reduced to 4 cups, about 40 minutes; season with salt and pepper. Transfer the shanks to a platter, pour the sauce on top and serve.