The French gourmet Robert Courtine called it the "poor man's truffle." George Washington proclaimed it "the most favored food that grows." Robert Louis Stevenson waxed grandiloquent when he dubbed it "the poetic soul" of a salad.
They were speaking of the onion. This humble root is, perhaps, the most useful, versatile, affordable and widely used food in the world. History bears this out. The ancient Romans commonly ate onion sandwiches for breakfast. The gladiators were massaged with onion juice before entering the arena. (Did this give them extra strength or simply ward off the lions?) And scallions and shallots were praised for their aphrodisiac powers by the Roman poet Martial.
Nowadays, the most common and simplest use for an onion is eating. Prepared any one of a hundred different ways, it's an epicure's morsel. Thinly sliced raw onions spice up commonplace salads and sandwiches. Slowly pan-fried or roasted in their skins, they acquire the sweetness of caramel. Saute'ed, onions give backbone to a myriad of soups, stews, and stir-fries.
But which onion? There are over 300 varieties to choose from. For the cook's purposes, onions can be grouped into two basic families: root onions and green onions. Here then, is a glossary to get you started:
Root Onions Yellow or Golden Globe
This is the basic all-purpose onion. Firm and round, it's covered with a dry, amber skin. It can range in size from a couple of ounces to over a pound. The yellow onion is quite strong, especially when raw. It keeps well, particularly when purchased in the fall.
Flattened at the top and bottom, this is another good all-purpose onion. The strength varies widely, depending on the soil and climate where it is grown.
These handsome onions add a splash of color to salads and salsas. They are usually used in their raw state, as they tend to turn gray when cooked. Purple and red onions are of medium strength. Among the more attractive varieties of red onions are the purplish Stockton Red and the teardrop-shaped Italian Red.
As the name suggests, the torpedo is a slender, elongated onion. It's oval shape makes it ideal for braising and serving whole. Torpedo onions come in both yellow and red.
This firm white onion is the size and shape of a Ping-Pong ball. Encased in a silver skin, it's another good onion for braising and for adding to stews, like boeuf bourguignonne.
Smaller than the silverskin, the pearl onion is covered with a papery white skin. Its flavor is quite strong, so it is almost always served pickled or cooked. Baby pearls are the onions of choice for making the pickled cocktail onions that adorn Vodka Gibsons. In their raw state, silverskin and pearl onions are difficult to peel. This can be facilitated by cutting a shallow "x" in the root end and blanching the onions in boiling water for 30 seconds.
This large brown or yellow onion originated in Europe, although probably not in Spain. Today, it is widely cultivated in the American Southwest. Its flavor is medium strong.
Native to the island of Bermuda, this handsome onion is flat-topped, ivory-colored, and delectably mild. Enjoy it raw (thickly sliced) on salads, sandwiches, and burgers. The season for Bermuda onions is April through June.
Vidalias are to onions what Jaguars are to cars. The juicy white onion owes its mildness to the low-sulphur loam in which it is grown. To bear the name Vidalia (pronounced vie-DAL-ia), it must come from one of 13 counties in southeast Georgia. Vidalia onions are uncommonly low in sulphur and high in sugar (12.5 percent), which makes them sweet enough to munch raw. Unfortunately, their high water content makes them very perishable so they lose their sweetness after two or three weeks. Vidalia onions are in season from May to mid-June.
Vidalia isn't the only region to lay claim to the nation's best onions. Just ask a farmer from Walla Walla, Washington. Walla Walla "sweets" are large, white, perfectly spherical onions with a delicate flavor and audible crunch. The crisp, sturdy layers make memorable fried onion rings. They are mild enough to be enjoyed raw on salads and sandwiches. Walla Walla onions are in season in July and August.
Another of the so-called "gourmet onions," Mauis grow in volcanic soil on the slopes of Mount Haleakala. Slightly flattened, yellow to pearl in color, they, too, are mild enough to eat raw. The season for Maui onions is April to August.
This sweet, round, yellow onion has triumphed at two national onion festivals. It owes its sweetness to the rich alluvial soil in which it is grown. The Imperial Sweet comes from southern California's Imperial Valley (which runs along the Mexican border), where it grows below sea level. In order to bear the name Imperial Sweet, the onions must pass a taste test conducted by the county agriculture commission.
Not to be outdone by Georgians or Californians, Texans have taken to growing sweet onions in the fertile Rio Grande Valley southwest of San Antonio. The pride of the region is the Texas 1015, a sweet, round, white, uncommonly juicy onion the size of a baseball.
This small, fragrant cousin of the onion is the cornerstone of French cooking. Without it there would be no bordelaise sauce or beurre blanc. The shallot is more delicately flavored than the onion, hinting at garlic, onion and chive. "It perfumes without imposing," observed the French gastronome Charles Moncelet. There are two types of shallots: gray and red. The former is said to have a more refined flavor, but each type has its partisans. Shallots have a relatively short shelf life of two to three weeks. Keep them in a basket where the air can circulate around them. Shallots for sauces and salads should be chopped so finely that they blow away in a puff of air. Garlic
This odoriferous bulb has been lauded and loathed throughout the course of history. These days we can't seem to get enough of it. Although there are more than 300 varieties of garlic, only three are grown in the U.S. Both pink garlic (harvested in August) and white garlic are grown in California, the former milder than the latter. Elephant garlic, recognizable by its large, easy-to-peel cloves, is the mildest. For maximum strength, crush the garlic in a press. Chopping produces a milder flavor, while roasting or poaching whole cloves yields the mildest taste of all.
Green Onions Scallions
Named for Ascalon, a biblical town in Judea, the scallion is prized for its long, green, mildly oniony shoots. Both the white base and green shoots can be used.
The green onion resembles the scallion, but it has longer stalks and a white, bulbous root. In my family, we mix chopped green onion and cream cheese to make a topping for bagels and lox. Green onions and scallions can be used interchangeably.
Chives are the smallest, mildest members of the onion family. Use them in any dish that would be overpowered by the more assertive flavor of scallions. The best way to buy them is rooted in a pot. Keep live chives on your kitchen window sill and use a scissors to snip off the desired amount as you need it. Chive buds make a lovely garnish for tomato salads. Baked potatoes are a sorry sight without them.
Found in Oriental markets, Chinese chives grow in long flat blades and have a strong, garlicy flavor.
The leek has the distinction of being the national emblem of Wales. (In the 7th century A.D., a Welsh king had his soldiers pin leeks to their helmets before a major battle. This enabled them to strike their enemies, not their comrades, and the Welshmen carried the day.) When buying leeks, look for pliable, fresh, green leaves. (A rigid leek has gone to seed and will be unpalatably pithy in the center.) The white base of the leek is the part you use: trim off the roots and the dark green leaves. To wash leeks, cut in half lengthwise, almost to the root. Roll the leek 90 degrees and cut in half lengthwise again. Then plunge the leek up and down in a bowl of cold water until the inside leaves are clean.
The name notwithstanding, the Welsh onion, also known as the bunching onion, is believed to have originated in Asia. Lacking bulb or shoots, it's believed to be the plant from which all other members of the onion family are descended.
Steven Raichlen is a freelance food writer and has a cooking school at the Snowvillage Inn in Snowville, N.H.