Epazote (Dysphania ambrosioides) is a pungent, polarising Mexican herb whose toothed, pointed green leaves carry one of the most arresting aromas in the kitchen — petrol, camphor, oregano, anise and citrus colliding at once. Native to central and southern Mexico and Central America, it is the herb traditionally simmered with black beans to tame their notorious gassiness, and it perfumes quesadillas, soups, moles and the corn dough of the Mexican table.