Artichokes, related to thistles, are native to the Mediterranean and grown in other parts of the world. These large flower buds have a tightly packed cluster of tough, pointed, prickly leaves that conceal pale green inner leaves and a gray-green base, which together make up the heart. Only the fleshy base of the leaves and the meaty base are eaten; the rest of the leaves and the fuzzy choke inside the heart are discarded. Artichokes are sold fresh year-round in sizes ranging from very small, or baby-about 1 1/2-2 inches (4-5 cm) in diameter-to very large, or globe. Select compact, heavy artichokes with tightly closed leaves; refrigerate in a plastic bag for up to 4 days. Artichokes are also available frozen, canned, and marinated.
To trim baby artichokes:
Pull off the tough outer leaves from each artichoke. Trim the stem even with the base and cut away the fibrous, dark green layer around the base, being careful not to trim the rich meaty crown that lies beneath it. Cut off about 1 inch (2.5 cm) from the top. To trim large artichokes: Put off about 2 inches (5 cm) from the top of each artichoke. Cut in half lengthwise and use a small, sharp-edged spoon to remove the fuzzy choke. Remove any interior leaves that have prickly tips. To prevent the artichokes from discoloring, rub the cut surfaces with a lemon half and immerse the trimmed artichokes in a bowl of water containing lemon juice.To steam artichokes: Place the trimmed artichokes on a steamer rack over (not touching) boiling water. Cover and steam until tender when pierced with a fork, 5-7 minutes. Remove the artichokes from the rack and let cool.