Lengua, better known as tongue, is a popular food in many cultures. It usually takes an acquired taste to fully appreciated the flavor of tongue. Beef, veal and pork are the more popular sources, but you can also find lamb or ox tongue. Beef tongue has a tender texture and one of the best flavors, according to the “Joy of Cooking.” Tongue is usually prepared by boiling or braising in liquid over several hours and thus a slow cooker is an ideal way to cook lengua.
Rinse and scrub the beef tongue with a kitchen brush. Pat dry with paper towels. Optionally, use tongue from veal, lamb, pork or other sources.
Place the tongue into a slow cooker and add just enough water to cover it. Optionally, instead of water, use beef stock, tomato sauce, red wine or a combination of these. Do not use too much liquid. There is no evaporation during slow cooking, so you should use around 20 percent less liquid than when cooking on stove top.
Slice vegetables of your choice to add flavor on the cooking liquid and, if desired, to serve the liquid as a sauce with the tongue. For example, slice one white onion, one carrot, three celery stalks and three cloves of garlic into large slices and add into the slow cooker.
Add one bay leaf into the slow cooker to add flavor to the liquid. Season the tongue and the vegetables with salt and black pepper to taste.
Cover the slow cooker, turn on and cook on low for 8 hours or on high for 4 hours.
Remove the tongue from the liquid and let it cool down. After it is cool enough to touch, remove the skin that wraps the tongue with a small knife. Also remove bones and gristle.
Slice the tongue into pieces and either serve cold or heat it up in the cooking liquid. Add some or all of the cooking liquid into a sauce pan. Bring to a boil and place the tongue slices in the hot liquid for 30 seconds. Serve the tongue with the cooking liquid, another sauce, mustard or horseradish cream. Optionally, use cold or hot tongue slices to make a sandwich or tacos.