Roux.

Roux

This recipe goes with Shrimp-Crab Gumbo.

1 1/2 cups vegetable oil
2 cups all-purpose flour

Heat oil in a large cast iron skillet over medium heat; gradually whisk in flour, and cook, whisking constantly, until flour is a dark mahogany color (about 30 minutes). Proceed with gumbo recipe, or cool completely, and store in an airtight container up to two weeks.
Yield
3 1/2 cups