Maui, Walla Walla and Vidalia -- you'd know sweet onions are special just by their curious names. Sweet onions make up only a small percentage of the crop and cost a little more than other onions, but their flavor makes them worth the extra cost.
Nobody knows for sure why some onions grown in specific regions taste as sweet as they do. When grown outside of these regions, these same onions would have the old familiar pungency. Sweet-onion growers in Hawaii, Washington and Georgia believe that special soil and gentle climate make the difference. Whatever causes the change, we were pleasantly surprised by their flavor, raw and cooked.
* Maui onions: In the 1930s a farmer on the island of Maui, Hawaii, planted onions on the side of a mountain. In that loamy, volcanic soil, the onions grow mild and sweet. They're available May through January and have a shelf life of one to two months. The raw onion has an almost sugary flavor. When cooked, the onion tastes mild.
* Vidalia onions: Farmers from four counties surrounding Vidalia, Ga., have been growing these onions for 40 years. The season is May through July. This variety has a shelf life of two weeks to one month. The onions have a very mild, delicate flavor.
* Walla Walla onions: Early in this century, a French soldier introduced seeds of an Italian-type onion to Walla Walla County, Wash., and Umatilla County, Ore. Over the years, these evolved into today's Walla Walla onion. The season is late June to mid-August; shelf life is one to two months. Raw onions have a slightly sweet flavor. Cooked onions are milder tasting than Maui pTC onions and have a soft texture.
Because of their high water content, sweet onions should be used within their recommended shelf life. For short-term storage, wrap onions in plastic wrap and chill. For longer keeping, wrap in netting to prevent bruising; hang in a cool, dry place.
* Add sliced or chopped raw sweet onions to salads, sandwiches or vegetable appetizer trays.
* Steam sweet onions with other fresh vegetables. Serve with a little snipped fresh or crushed dried herb.
* Stir-fry in a little margarine or butter to serve with beef, pork, poultry or seafood.
* The flavor of sweet onions will be lost in intensely-flavored or long-cooked mixtures. Use regular onions in these dishes.