Sassafras albidum, a tree common throughout eastern North America, once provided a principal ingredient in root beer: safrole oil, which was extracted from the root bark. The oil was banned by the FDA in 1960 for commercial use, but you can catch a whiff of its distinctive aroma by tearing into a fresh sassafras leaf. The dried leaves, which contain only an insignificant amount of safrole oil, still have a famous culinary use: They are ground into the powder called filé, which helps thicken some varieties of gumbo.
You won't find that beloved Louisiana stew at Harry & Ida's, which may be the only shop in the city that sources foraged sassafras leaves to prepare its own filé. Instead the powdered dried leaves are incorporated in a pastrami-scrap hot dog ($10), dressed with a parsnip, onion, and horseradish relish, dill, and shiitake mayo. The housemade filé does land an earthy counterpunch to the brightness and crispness of the relish — but imagine how it might also be put to use in some local Creole kitchen.
Harry & Ida's Meat and Supply Co.
189 Ave. A (11th-12th Sts.), Manhattan