Roux is an essential element of sauce-making. It serves as thickener and binder. There are dark, blond or white roux, depending on their purpose.

White roux is used as a binder for white sauces, since it doesn't color them.

Roux will keep for several days in the refrigerator.

1. In a heavy saucepan, melt the butter until it begins to foam. 
2. Off the heat, add the flour all at once. Return to the heat and stir constantly until the mixture comes away from the bottom of the pan. 
3. For white roux, cook about 3 minutes without letting it color, so that the raw taste of the flour has time to dissipate.