Sesame is one of the oldest cultivated plants, and is probably the oldest oil seed crop. It features prominently in cuisines from Greek to Arabic to Chinese to Japanese. It’s a versatile ingredient. The toasted seed is used in cooking, and baking; for sweet and savoury dishes. The oil is used as a seasoning. The paste is used as a thickening agent, or a sauce.
Toasted sesame seeds are common as a garnish, or a flavouring agent, as in kinpira renkon. They are white, or (less often) black; and can be sprinkled onto food whole, or ground. You can buy these easily in Asian grocers. Watch out, they’ll get moths if you let them sit around too long.
Sesame oil makes a delicious addition to soup, or stir fries. It’s dark brown in colour, and has a very strong, distinct flavour. There’s not really any substitute for it. It’s only added at the end of cooking. Don’t actually fry with it, because it has a low smoking point and can burn.
The dark-brown toasted sesame paste of Asia is made with the whole seed, hull and all, and has a different texture and taste than tahini. It’s used a lot in Chinese sauces (such as hoisin), and noodles. You can substitute smooth peanut butter, or tahini, if you don’t have it.
Similar to the Asian paste, but paler, softer, and lighter tasting. It’s the most important ingredient in the ubiquitous Middle Eastern tahina sauce; and is a major component of hummus and baba ghanoush.
Sesame originated in the Fertile Crescent, and has been domesticated for at least 3000 years. It’s been used for much longer than that, and was an early component of trading between Mesopotamia and India. Because it’s drought tolerant, it was soon widely cultivated in dry areas around the world.