T he rate at which you add a liquid to a flour-and- butter roux can have a drastic effect on the smoothness of the final sauce, as well as its thickening power To demonstrate this, try the following experiment Materials • 2 tablespoons butter • 2 tablespoons all-purpose flour • 2 cups milk • 1 pound cheese, grated Procedure Cook 1 tablespoon of the butter and 1 tablespoon of the flour in a small saucepan over medium heat, stirring constantly, until light golden blond, about minute Rapidly add cup of the milk, whisking to combine Allow to come to a boil, stir in half of the cheese, and set aside Repeat with the remaining butter, flour, and milk, this time very slowly whisking in the milk over the course of 15 seconds Allow to come to a boil, stir in the remaining cheese, and set aside Results Rapid ...Allow to come to a boil, stir in the remaining cheese, and set aside Results Rapid