Dessert & Treats Recipes Cake Recipes Fillings & Frostings Buttercream Frosting Recipes Basic Buttercream Filling and Frosting 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 July 9, 2019 Print Rate It Share Share Tweet Pin Email Prep Time: 15 mins Total Time: 15 mins Yield: Makes 5 1/2 cups Use this recipe for both the Salted-Caramel Whoopie Pies and the Powdered-Sugar Coconut Layer Cake. Ingredients 4 sticks unsalted butter, room temperature 6 cups confectioners' sugar 1 teaspoon pure vanilla extract Directions Beat butter on medium-high speed until pale and creamy, about 2 minutes. Reduce speed to medium and add sugar 1/2 cup at a time, beating after each addition, until combined, 1 to 2 minutes. Beat in vanilla. Use immediately, or store in an airtight container in refrigerator up to 3 days. Before using, bring to room temperature and beat on low speed until smooth. Rate it Print