Making a Roux

Equal parts fat and flour, cooked together, form the thickening base for most of classical French cooking. A white roux thickens bechamel in minutes. A blonde roux builds veloute. A dark roux, cooked for 45 minutes until it smells like popcorn, is the soul of Cajun gumbo. The technique is absurdly simple but requires attention — too much heat and the flour burns, too little and the sauce tastes pasty. Once you can make a roux, you can make any mother sauce.