Beurre manié (French "kneaded butter") is a dough, consisting of equal parts of soft butter and flour, used to thicken soups and sauces. By kneading the flour and butter together, the flour particles are coated in butter. When the beurre manié is whisked into a hot or warm liquid, the butter melts, releasing the flour particles without creating lumps.
Beurre manié should not be confused with roux, which is also a thickener made of equal parts of butter and flour, but which is cooked before use.
Because Beurre manié contains uncooked flour, liquids thickened using Beurre manié dough may have an undesirable floury or pasty taste due to the uncooked proteins in the flour. For this reason, it is important that the Beurre manie is allowed to cook adequately, rather than being added to a dish immediately before serving.
Beurre manie is also used as a finishing step for sauces, imparting a smooth, shiny texture prior to service.