ATLANTA (CNN) -- Sip a Vietnamese soup or savor a Thai shrimp dish and you may notice a subtle lemony undertone that lingers on the palate. That flavor infusion comes from lemongrass, an unsung hero of the Southeast Asian kitchen that's slowly making its way into our culinary consciousness.

As its name suggests, lemongrass is, in fact, a grass -- a hardy perennial that thrives in the tropical climates of Southeast Asia and Latin America. It looks a bit like a scallion or a leek, but is taller and paler with a distinctly citrusy flavor. It is sometimes called citronella or sereh. Like most herbs, it comes in many varieties.

Lemongrass gets its aroma from citral, an essential oil used in everything from aromatherapy treatments to soaps to insect repellents. Dried lemongrass leaves can be brewed into tea or sprinkled into potpourri. But savvy chefs know the best place for lemongrass is in their food, flavoring dishes as diverse as ceviche and sorbet.

A versatile seasoning

"It goes well with everything," says chef Jean-Georges Vongerichten of New York's Vong and Jean Georges restaurants. "It goes well with chicken. I love it with tomato, too. It mixes very well with everything." Chef Alan Wong, of Alan Wong's Restaurant in Honolulu, agrees. "It's very versatile. It goes almost with anything -- fish, seafood, chicken, beef."

Vongerichten first tasted lemongrass on a trip to Bangkok in 1980. For the 20 years since, he's been using it to infuse his innovative French fare with the taste of Thailand. "It changed my way of cooking," he enthuses. "It's my favorite herb." Vongerichten blends lemongrass with garlic, Thai fish sauce and chiles to make a sauce for chicken, and he adds the herb to Thai-inspired soups.

Simple fish dishes also benefit from the lemony leaves. Vongerichten recommends adding a stalk of lemongrass to the water used to steam a fillet, or as the crowning touch in a papillote of fish on a bed of spinach or mushrooms. Wong favors adding lemongrass to broths and dressings. "It's an excellent aromatic," he explains, that combines well with other Asian ingredients such as ginger and kaffir lime leaves.

'Smash it'

Lemongrass is easy to use because it imparts its flavor very quickly, especially when added raw to a marinade or simmered in a clear broth. Although it's available dry and powdered, most recipes call for fresh lemongrass.

The stalks can be bought at most Asian markets and even some well-stocked supermarkets. Or you can grow your own. If you can't find a plant at a nursery, you can buy the seeds from an Internet seed site. Just be sure to give the plant plenty of sunshine, and bring it indoors when the weather gets cool. It may take a while for your home-grown plant to get as big as the stalks you find in the supermarket.

When choosing lemongrass, look for stalks that are firm, full and pale green -- the pale color indicates freshness. The bottom of the stalk may be woody, but it shouldn't be shriveled. Bend the stalk and smell it. Choose a moist, fragrant one.

To prepare lemongrass for your recipes, wash it thoroughly, peel off the tough outer leaves and trim the ends. You'll need a sharp knife, as the stalks are very fibrous. Use the heart of the stalk -- the bottom four to six inches up to the point where the leaves branch out. Then get out your mallet. "It's important to smash it before you chop it or slice it," instructs Vongerichten. "It gets the oil out."

Because of its tough texture, lemongrass is usually added to recipes whole, then removed and discarded before serving, much like a Bay leaf. But the center portion can be eaten if it's finely chopped.

What to do if you can't find fresh lemongrass? Substitute 1 tablespoon of dried lemongrass for each fresh stalk. If dried isn't available, try several strips of lemon peel per stalk. Chefs warn, though, that the effect won't be quite the same, since lemongrass has a more subtle, delicate flavor than lemons or limes.

With so many options for cooking with lemongrass, it may take some experimentation to find your favorite use for this versatile ingredient. But the flavorful results will be well worth the effort.

by Eleni Berger
CNN Interactive Editor
CNN.COM