It was, I eventually found out, asafetida ("ass-uh-feh-TEE-dah")—resin made from the sap of Ferula foetida, a plant that grows in India, Afghanistan, and Iran. The name derives from the Persian asa, "gum", and the Latin foetida, "stinking". (The German word for it, Teufelsdreck, translates, even more unappetizingly, as "devil's dung".) In medieval times, asafetida was reputed to ward off witches. The ancient Romans found it to be the only acceptable substitute for silphium, an herb that disappeared (due to overcropping) during the time of Emperor Nero (A.D. 37-68). It is a powerful seasoning—a mere pinch will impart a trufflelike flavor to any unsuspecting dish—but with cooking, it magically loses its sulfurous scent. Today, the ingredient is used mostly in India, where it is called hing. Jains and Hindu Brahmins use it in place of onions, which are prohibited in their cooking because of their strong smell.