Roux

Melt the butter in a heavy saucepan over medium-low heat. Add the flour and whisk continuously until the mixture is smooth. Continue cooking and whisking for 3 to 5 minutes for a pale roux suitable for cream sauces, 8 to 10 minutes for a golden roux, or 20 to 30 minutes for a deep brown roux. Adjust the heat as needed to prevent burning. Remove the roux from the heat when it reaches the desired color and use it immediately as the thickening base for a sauce, soup, or stew.