When European explorers began to search for a route to the Indies by traveling west, they were looking for spices like nutmeg and cinnamon.

When the explorers came to the area that was to become Louisiana they found a spice in New Orleans called filé.

Unlike other spices, this New World spice was not heralded as a new sensation and introduced into the courts of Europe. It was not recognized. It was ignored.

Native Americans used filé as both a seasoning and a thickener. Filé was made from the dried leaves of the native sassafras tree that were crushed into a powder. These indigenous people also ate the new shoots of the sassafras tree.

The thick soups or ragouts that have collectively became known as gumbos had to be thickened with something, and file became one of those thickeners. Before the widespread availability of flour in Louisiana, filé was likely a welcome way for Europeans to make gravy.

Elizabeth M. Williams is the president and director of the Southern Food & Beverage Museum and author of New Orleans: A Food Biography.