An essential ingredient in Asian cooking, sesame oil is one of the most unique, fragrant and richly-flavored oils you can keep in your pantry. Its slightly sweet, nutty taste adds depth to steamed vegetable and brings warm notes to salads and vinaigrettes; it even adds intrigue to popcorn or ice cream.
Sesame seed oil is derived from sesame seeds (Tanzania is the world's biggest producer), and comes in two varieties: regular and toasted. Home cooks should note, though, that they're not interchangeable.
Regular, untoasted sesame oil (often labeled simply "sesame oil") is made from raw, pressed sesame seeds. It has a relatively high smoke point (410 degrees), so you can use it as you would other neutral oils, such as canola or grapeseed. Reach for regular sesame oil if you're shallow frying or roasting; it's a solid all-purpose oil.
Then there's toasted sesame oil—which is almost a different ingredient entirely. It's made from toasted (or roasted) sesame seeds, and this seemingly minor step vastly changes the oil's flavor. It's at once delicate and complex, since heating the seeds before extracting the oil enhances their taste (just as toasting nuts, spices, and seeds before cooking with them draws out their flavors).
Darker in color than regular sesame oil, toasted sesame oil is pricier, too, but a little goes a long way. Don't use it for frying; since it already has such rich flavor, heating it again will give it a burnt, slightly bitter taste. Instead, drizzle it sparingly over foods, as a condiment, just before serving them. Think: fried rice, noodle soups, stir-fries, and steamed vegetables. It's also wonderful in Asian sauces and salad dressings.
Both varieties of sesame oil are sold in most supermarkets, alongside other cooking oils, and you can find them for about $7 to $12.