In our recipes we do not sift all-purpose flour. To measure, spoon through it lightly in its container, lightly spoon it into a dry measuring cup, then level the top with a straight-edged tool. We also do not sift cake flour in our recipes, measuring it as above. An exception to this is angel food cake, where we do sift it with powdered sugar to lighten it for this very light-textured cake. For this cake we would measure as above after sifting it, then we sift it with the powdered sugar.