Food & Cooking Recipes Dessert & Treats Recipes Royal Icing for Citrus Sugar Cookies Be the first to rate & review! By Martha Stewart Test Kitchen Martha Stewart Test Kitchen The recipes developed by our test kitchen team have undergone a rigorous process of development and testing, ensuring that every element is optimal, from ingredient amounts to method and cooking time. This process includes triple-testing recipes to ensure they meet our high standards. The many stellar cooks and food editors who have been part of our team include Sarah Carey, Lucinda Scala Quinn, Jennifer Aaronson, Shira Bocar, Anna Kovel, Greg Lofts, Riley Wofford, Lauren Tyrell, and Lindsay Leopold. Editorial Guidelines Updated on March 31, 2020 Print Rate It Share Share Tweet Pin Email Yield: 3 cups The secret to perfectly decorated sugar cookies for the holidays is royal icing. This recipe, which is easy to work with and sets quickly, uses confectioners' sugar, pasturized egg whites, and cream of tartar. Use this royal icing for frosting our Citrus Sugar Cookies. Ingredients 4 cups confectioners' sugar, sifted 5 tablespoons pasteurized egg whites ½ teaspoon cream of tartar Directions Using an electric mixer on low, combine confectioners' sugar, egg whites, and cream of tartar; beat on high until icing is whipped and opaque, about 2 minutes. Thin with water as needed to make a stiff but spreadable icing. Rate it Print