Food editor Melissa Roberts shows a few different ways to thicken gravy. The first way that is shown is using either arrowroot or cornstarch. Both of these ingredients are gluten free and must be dissolved completely in cold water before adding to hot liquids as clumping will result if added straight. The next method to thicken your gravy is called a buerre manie'. A beurre manie' is French for needed butter. This method is a paste made by combining three tablespoons of butter and three tablespoons of flour. Smooth the ingredients together until a fine paste is created. You then add this paste to the liquid and heat over a brisk simmer until desired thickening takes place. Both methods will give proper thickening results. The beurre manie' will result in much smoother gravy than the arrowroot or cornstarch.