For those who feel they haven't been getting enough thymus gland or pancreas in their diets, have we got a culinary delicacy for you! Sweetbreads are the thymus glands and/or pancreas of calves, lambs and piglets under one year old. These glands are classified as offal in culinary circles, along with other parts such as gizzards and intestines. Unlike other members of the offal family, however, sweetbreads are considered a delicacy among those familiar with haute cuisine. Sweetbreads can be prepared in a number of ways, from sauteeing to deep frying, although the steps between the butcher shop and the table can be tricky and time-consuming.

There are two separate glands which fall under the category of sweetbreads, the thymus and the pancreas. The thymus gland is located in the young animal's neck and is primarily responsible for excreting protective t-cells as part of the immunity system. Thymus sweetbreads are more irregular in shape than pancreas sweetbreads, and are also considered to be less flavorful. For this reason, most thymus sweetbreads are less expensive than their pancreatic counterparts.

The pancreas varieties of sweetbreads are located near the animal's stomach, and produce insulin and other digestive enzymes. Pancreas sweetbreads are generally larger and rounder in shape than thymus sweetbreads. Between the two varieties, the pancreas sweetbreads of veal calves are the most sought after by connoisseurs.

Both the thymus and pancreas forms of sweetbreads must be properly prepared before they can be cooked. Raw sweetbreads often have a layer of fat and a sinewy outer membrane which must be peeled away first. Many professional chefs recommend soaking the sweetbreads in an acidic bath made from water and an acidic liquid such as vinegar or wine. The sweetbreads should be soaked in this bath for several hours, and the water should be changed out several times. This process is said to make the membrane easier to remove and also drain off any remaining enzymes and blood. Ideally, sweetbreads should be white or slightly pink in color. The older the animal, the redder the sweetbreads.

Once the sweetbreads have been peeled, deveined and washed, they can be blanched for a short time to reduce later cooking time, or they can be breaded and deep fried immediately. Barbecuing and grilling are also popular ways to prepare sweetbreads. The taste of sweetbreads is said to be reminiscent of bacon, although some say the main attraction of sweetbreads is the silky texture, not necessarily the flavor.

While sweetbreads may be difficult to find on many American menus, they are popular in other countries, most notably Turkey and Argentina. Sweetbreads are frequently barbecued or seared over open grills in those countries. Sweetbreads can be specially ordered in butcher shops, but it pays to know which variety you may prefer or are able to afford. Thymus sweetbreads are less expensive than pancreas sweetbreads, but they may be less flavorful. It is important to prepare sweetbreads within 24 hours of purchase, and avoid buying sweetbreads which are deep red in color.