A soft, fatty tissue found in the hollow center of an animal's leg bones and, though not as plentiful, in the spinal bones. It isn't widely consumed in the United States, but marrow is considered a delicacy by many Europeans and is the highlight of the famous Milanese specialty osso buco. Marrowbones (those that contain marrow) can be purchased at meat markets and most supermarkets (though special ordering may be necessary). They should be wrapped, refrigerated and used within a day or two of purchase. Marrow is extremely light and digestible. It can be cooked in the bone (and removed afterwards) or it may be removed first and cooked separately. The common methods of preparation are baking or poaching, after which the marrow is often spread on toast and served as an appetizer. A special long, narrow utensil called a marrow spoon or scoop can be used to extract the marrow from the bone. Marrow is also added to soups for body and flavor. It has the same calorie count as beef fat and contains a small amount of protein.