First, sweetbreads should be soaked in cold water for a minimum of several hours (many chefs soak them up to 24 hours). This removes any traces of blood. This soaking, or degorging, produces a whiter and milder tasting sweetbread (both of which are desirable characteristics).
- After soaking, the sweetbreads should be blanched. Begin by placing them in a pot and covering them with cold water. (Some chefs add a touch of salt, and lemon juice or vinegar to the blanching liquid.) Bring them to a boil.
- Remove sweetbreads from the blanching water and plunge them into ice water. Blanching further removes impurities, makes them whiter, and firms the tissue so that it can be easily trimmed and portioned.
- To trim sweetbreads, remove any visible veins, gristle, or the thick exterior membrane that envelops the organ. This is best done by using your fingers.
- After blanching and trimming, the sweetbreads should be pressed. Lay them on a clean towel on a tray or shallow pan. Do not stack the sweetbreads.
- Place another towel on top and cover with another tray or pan of the same size. Place a heavy weight on top of the last tray. A heavy pot filled with water is ideal.
- Place the weighted sweetbreads in the refrigerator and allow them to be pressed for at least two hours. (They can be pressed up to 24 hours.)
- After pressing, the sweetbreads will be firm enough to slice into medallions by cutting on a slight bias. These medallions can then be easily sautéed, fried or grilled.