Roux Roux Roux () is flour and fat cooked together and used to thicken sauces. Roux is typically made from equal parts of flour and fat by weight. The flour is added to the melted fat or oil on the stove top, blended until smooth, and cooked to the desired level of brownness. Butter, vegetable oils, bacon drippings or lard are commonly used fats. Roux is used as a thickening agent for gravy, sauces, soups and stews. It provides the base for a dish, and other ingredients are added after the roux is complete. The fat is most often butter in
Butter lemon juice. Hollandaise and béarnaise sauces are emulsions of egg yolk and melted butter; they are in essence mayonnaises made with butter instead of oil. Hollandaise and béarnaise sauces are stabilized with the powerful emulsifiers in the egg yolks, but butter itself contains enough emulsifiers—mostly remnants of the fat globule membranes—to form a stable emulsion on its own. "Beurre blanc" (white butter) is made by whisking butter into reduced vinegar or wine, forming an emulsion with the texture of thick cream. "Beurre monté" (prepared butter) is melted but still emulsified butter; it lends its name to the practice of "mounting"