Lamb Shanks Braised in Red Wine

Heat the oven to 425 degrees. Season the shanks with salt and pepper. In a large, high-sided ovenproof pot, heat the oil until barely smoking. Sear the shanks in batches on all sides until golden brown. Put all the shanks in the pot; add the peppercorns, bay leaves, stock, wine, garlic, celery, carrots, onion, and mushrooms. Put the pot in the oven and cook, turning the shanks every 1/2 hour, until the meat is very tender but still on the bone, about 2 hours. (If making ahead, refrigerate the shanks and cooking liquid separately. Before reheating, remove the fat from the liquid. Put the shanks and the liquid in a covered roasting pan in a 400 degrees oven for about 20 min.)

Remove the shanks and some mushrooms and onions and cover them with foil. Strain the braising liquid into a medium saucepan, degrease carefully, and simmer gently until its flavor is intensified and its volume is reduced by about a third. Serve the shanks on top of the Roasted Garlic and White Bean Puree; ladle the sauce over the lamb. Serve some of the mushrooms and onions on the side.