Roux is used for thickening, giving body to sauces, etc. It is made by cooking together an equal quantity of butter and flour for about five minutes, or until the flour has lost the raw taste. When the roux is cooked, draw the saucepan to a cooler part of the range, and add the liquor (stock or milk) slowly, in the proportion of one cupful of liquor to one tablespoonful each of butter and flour, and stir until smooth. If the roux is for white sauce do not let the flour color. If for brown sauce, let it cook until brown, but be careful that it does not burn. If more flavor is wanted, fry a few slices of onion or other vegetables in the butter before adding the flour. Sauces thickened in this way are much better than those in which uncooked flour is used. In making roux do not use more butter than flour. Where more butter is required in a sauce, add it, in small pieces at a time, after the other ingredients are mixed with the roux. This will prevent an oily line forming.