Filé powder is a native North American herb made from dried and ground sassafras leaves. It has a woodsy, earthy flavour reminiscent of root beer. It is as important as a thickener as a flavour most notable for the quintessential Cajun/Creole soup/stew: Gumbo, as in a crawfish pie and a jambalaya and a filé gumbo son of gun we'll have big fun on the bayou. Filé roughly means stringy, and this is important: It must be added to gumbo at the end of cooking, off the heat if boiled, it will transform your gumbo into a stringy, unappetizing mess. It is often passed at the table and added to taste.