For many cooks (those not living in Southeast Asia, anyway), the hardest part about making Thai curry paste is finding a few of the ingredients. Some of what you need is waiting for you at your supermarket, but for the ingredients below, you may need to visit an Asian market.
A. Lemongrass (tah krai): With a floral lemony scent and a delicate citrus-like flavor, lemongrass shows off in a wide array of Thai dishes. It’s standard in curry pastes and valued in traditional medicines as well. It’s becoming more mainstream, so some supermarkets carry it, but Asian markets are a better bet for the freshest lemongrass. Look for sturdy, fibrous, pale-green stalks. To use, trim away the top portion of each stalk, leaving a 4-inch-long section, including the base. Pull off any dry, tired outer leaves before chopping or slicing as needed. To keep lemongrass fresh, wrap stalks loosely in a plastic bag and refrigerate them for five to seven days. To freeze lemongrass, trim the tops, wrap well to make them airtight, and freeze for up to six weeks. Use directly from the freezer without thawing. Avoid dried and powdered lemongrass, as they retain none of the flavor or aroma you need.