Called the "king of vegetables," the onion has a dominant flavor and is extremely versatile. There are two general flavors--mild an pungent--and two shapes: round and elongated. Onions can also be grouped by the time of year they're available.
• Spring/summer onions are available April through August. They have a mild sweet flavor and are more fragile that fall/winter onions. Vidalia and Walla Walla are two popular spring/summer onions.
• Fall/winter onions are available August through March. They have a robust flavor and may be white, yellow or red in color. They are firm and store well in a cool, dry, dark place that's well ventilated.
• Green onions, whice are immature onions picked before the bulbs develop, are available year-round.