Filé (FEE-lay) powder is the ground leaf of the sassafras tree, historically used by Choctaw cooks and healers in what's now Louisiana. As European settlers moved into the area, they adopted the Choctaws' use of filé, which became a permanent fixture in the quintessential dish of Cajun and Creole cuisine—gumbo.
Most authorities agree that gumbo takes its name from kingombo, the African word for "okra." But a vocal group of resisters insist that gumbo derives from kombo, the Choctaw word for "filé." Perhaps it's a moot point, because filé and okra seldom appear in the same pot. Virtually every gumbo-of which there are probably thousands-starts with roux. From there, they gain further thickening from either filé or okra. Early cooks made their choice based on season. When okra was plentiful, it went in the pot. Otherwise, it was filé.
For the Cajun French who named it, filé roughly translates as "stringy," and overcooking can have just that result, especially if the gumbo gets reheated: a common practice, since gumbo's better the second day. Add filé toward the end of cooking, or do as some folks do—bring it to the table to be stirred in by the diner. Filé has a faintly grassy taste that's often compared to thyme. New Orleans food authority Poppy Tooker speculates that the earliest Cajuns must have thickened their stews with filé alone, as they lacked the wheat flour to make a roux.
—By Jo Marshall, a food writer in Deephaven, Minn.