The notorious asafetida is the strong-smelling, even stinking, dried brownish resin extracted from the root of a plant (Ferula assafoetida) that grows wild from the eastern Mediterranean to central Asia.
In central Asia, especially India and Iran, asafetida has remained an important culinary spice and herbal medicine. In India, some people don’t eat onions and garlic for religious reasons, substituting asafetida instead; however, in northern Indian cooking, asafetida is often combined with either garlic or onion. In southern India, asafetida is even more popular and shows up in the Tamil spice mixture sambar podi, which generally seasons vegetables, not meats, because vegetarianism is more prevalent in southern India.
What to buy: For stronger flavor, buy asafetida resin; for a milder spice that’s easier to use, buy powdered asafetida. Yellow asafetida is milder than brown.