Creole Gumbo File Powder, sometimes spelled filA powder, and pronounced FEE-lay/fih-LAY, is a thickening powder and seasoning used in Creole and Cajun cuisine made in Louisiana and areas around the Gulf of Mexico. File powder is made from the dried and ground sassafras leaves. It has a rich yet cool eucalyptus-like sweet smell and taste. Add sassafras powder to dishes after cooking to thicken and flavor sauces, soups, and stews. Blend well. Use it in gumbo with sausage, crawfish, chicken, and vegetables like tomato and okra. Sassafras leaves have been used as a seasoning by American Indians for generations. They gained popularity as a seasoning African American cuisine around the time of the Civil War. It is thought that file powder was originally used for practical purposes: the okra often used to thicken gumbo is only available when in season, so to make gumbo in the winter something dried and readily available had to be found. Now file powder and gumbo are inseparable. Store gumbo file powder for up to six months in a cool, dry, airtight place.