The cardoon (Cynara cardunculus) is a member of the thistle family and is thought to be an early ancestor of the artichoke. It orinally was a wild plant native to Northern Africa and the ancient Greeks enjoyed it edible stalks. From Greece the plant spread to Italy and throughout Europe. Quakers brought the plant to America in the 1790s. Today the plant is still very popular in Italy, Spain, France, and North Africa.
Cardoon plants can grow to be five feet tall and produce a huge purple flower similar to a thistle flower. They are planted in April and are harvested around September and October. The plant produces thick, edible stalks that look like celery. These stalks are often wrapped with cloth while they are growing to prevent exposure to sunlight. This makes the stalks gray and gives them a mild, bittersweet flavor similar to an artichoke.
If you would like to sample some cardoon stalks, good luck. The plant is extremely rare and difficult to purchase. Try looking for cardoon stalks in farmer's markets and well-stocked supermarkets in the fall. The plant is also commonly imported from Italy, so also try looking for them in Italian markets. When selecting stalks, look for crisp, unbruised ones, the smaller the better. You can store them in the fridge wrapped in a moistened paper towel for about a week.
When you are ready to eat the cardoon, toss any tough stalks and trim off the leaves. The strings in the stalks may be tough and can be removed with a vegetable peeler. Cut the stalks into pieces and throw away regions of the stalk that are too tough to cut. Soak the pieces in water with a splash of lemon juice for about half an hour. At this point, any tender, young pieces can be served raw with a sauce. Tougher pieces can be boiled in water with lemon juice to prevent darkening. This will take anywhere from 15 minutes to an hour, depending on the desired tenderness. The boiled pieces are good in stews and thick soups or served on their own sauteed with butter or olive oil and a bit of grated cheese. Artichoke hearts and celery can be used as substitutes.
Cardoons may also be known as chardoon, cardi, Texas celery, or cardoni.
The Joy of Cooking, revised edition, 1997.