In a large, heavy-bottomed braising pan or Dutch oven, heat the oil to very hot. Brown the lamb shanks 2 at a time. Remove them to a side platter.

Add the onions and cook until lightly colored. Add the garlic and cook for 1 more minute. Return the lamb shanks to the pan and cover 2/3 up with chicken stock. On low flame, cook for 1 hour, repositioning the shanks for even cooking until very tender. Remove the shanks and strain the stock.

Preheat oven to 400 degrees.

Skim off most of the fat and bring stock to slow boil in the pan. Blanch the potatoes in the stock for 2 minutes. Transfer to roasting pan and set in oven. Blanch and transfer carrots, then parsnips and then zucchini in same manner. Roast vegetables for 10 minutes.

Add lamb shanks to roasting pan with vegetables after 5 minutes and roast them for the final 5 minutes. Add balsamic vinegar to stock and reduce over high heat until thickened. Adjust vinegar to taste. Serve shanks with vegetables and sauce.

This recipe yields ?? servings.