Basic Veloute-White Sauce

Melt 1/3 cup butter in a saucepan, mix in 1/3 cup flour, and cook the roux for a few minutes. Add 3 cups white chicken or veal stock, ½ teaspoon salt, and a little pepper and cook the mixture, stirring constantly, until it thickens. Cook the sauce, stirring occasionally, until it reduces to about 2½ c ups and is very thick but light and creamy.