Asafoetida is a resin from a type of giant fennel. It exudes a strong, somewhat nasty odour. Used in small quantities, Asafoetida provides an onion-garlic flavour that enhances many dishes. It's often used in lentils to help prevent flatulence. It was believed that asafoetida enhanced singers voices, and during the Mughal aristocracy, court singers in Agra and Delhi would eat a spoonful of asafoetida with butter, then practice on the banks of the river Yamuna.