taken from http://www.seriouseats.com/2014/09/you-should-use-thai-basil-southeast-asian.html
Why You Should Be Cooking With Thai Basil
Thai basil's sturdy leaves and spicy anise flavor make it the perfect companion to food from all over Asia. [Photograph: Alyss, Flickr
With summer drawing to a close, I'm making full use of my very favorite fresh herb: basil. Before those luscious-smelling bouquets of bright green leaves become more scarce at the market, I'm throwing them by the handful into almost everything I make: tomato salads simply adorned with olive oil and salt; hearty vegetable stews bright with both sweet and spicy peppers; and, of course, pesto, pesto and more pesto, which I stash by the quart container in my freezer.
Like many home cooks, I'm most familiar with plain ol' sweet basil, whose wide, tender, green leaves make their way into the majority of the Italian and Mediterranean dishes we make at home or order out. But the world of basil varieties is a vast one, encompassing over 100 cultivars whose flavors range from mild and floral to spicy and complex.
Thai basil does wonders for northern Thai larb. [Photograph: Robyn Lee]
One cultivar especially worth seeking out is Thai basil,* which is now grown domestically and is increasingly common in Western markets and specialty Asian groceries. If all you've ever known is Italian sweet basil, you'll may be surprised by its crisp pungency that plays particularly well with Southeast Asian food. It adds a fresh, herbal-licorice flavor not quite like anything else.
* Which is different from holy basil, a more medicinal-tasting herb also used in Thai cooking.
With purple stems whose color intensifies as the plant grows larger, Thai basil's leaves are sturdier than floppy sweet basil, and its slim, pointed shape more closely resembles mint than its Italian cousin. Its flavor is markedly different than Italian sweet's: when tasted alone, its unmistakable liquorice-y notes are most salient; overall, Thai basil is bolder and slightly spicier than the sweet kind.
Thai basil brings pungency to Taiwanese three cup chicken. [Photograph: Cathy Erway]
It's a versatile herb, though, and good to have on hand for a punchier caprese or ratatouille, but its true boon is the anise intensity it brings to East and Southeast Asian dishes from Thai coconut milk curry to Taiwanese three cup chicken. Tried these dishes at home but felt they lacked a certain fresh pungency? Thai basil can solve that problem.
If you live in a city with a Southeast Asian population, you can likely find Thai basil in specialty groceries catering to those communities; additionally, some farmers are beginning to grow and sell the herb at local farmers markets. (You can also order them online.) Like Italian sweet basil, fresh Thai basil leaves should have a bright color and a not-droopy demeanor, and they don't take too well to drying, so take the time to seek out fresh versions.
Thai basil is wonderful eaten raw, slivered, and added to salads, both your plain old cucumber-tomato salad or something meaty like northern Thai larb. But its hardy leaves stand up especially well to cooking—their flavor infuses readily into food and the leaves don't wilt quite as much as Italian sweet basil's would. Try Thai basil in simmered dishes like Taiwanese braised eggplant and green curry as well as high-heat stir-fries such as Thai basil chicken and Thai tofu (traditionally made with holy basil, but great with Thai basil, too).
Looking for more ways to use your Thai basil? Some more recipes right this way: