The importance of sifting powdered sugar

The lightest, fluffiest vanilla buttercream frosting | completelydelicious.com

In my tutorial on How to Build a Layer Cake, I share several ways to give your cake that professional look. One sure bet to give yourself away as an amateur cake baker is lumpy frosting. To avoid visible clumps of powdered sugar, simply sift the powdered sugar with a sifter or mesh strainer before adding it to your recipe.