The long hollow limb bones that contain a soft, fatty tissue called marrow. Marrow is traditionally used to flavour bordelaise sauce, is contained in veal shanks used for osso buco, is added to risotto Milanese, or is simply eaten on toast. It can be roasted in the bone or taken out and poached. The marrow is extracted using a special spoon or, less delicately, sucked out of the cut marrowbones. Marrow can also be melted like butter and used to cook vegetables and meats.