How to Make a Dark Roux in the Oven

Preheat the oven to 350 F. In a heavy iron skillet or Dutch oven, combine the flour and oil; whisk until the mixture is smooth and lump-free. Place the pan with the roux in the oven for approximately 2 to 2 1/2 hours, stirring it thoroughly every 20 minutes until the roux is the desired color: light, medium, or dark.