Dessert & Treats Recipes Cake Recipes Fillings & Frostings Buttercream Frosting Recipes Peanut Butter Buttercream 3.6 (127) 1 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 May 16, 2017 Print Rate It Share Share Tweet Pin Email Yield: 1 cup Use this recipe to make our Peanut Butter Whoopie Pies. Ingredients ⅔ cup natural, creamy peanut butter 8 tablespoons (1 stick) unsalted butter, softened ¾ cup confectioners' sugar Fine salt (optional) Directions Cream peanut butter and butter in the bowl of an electric mixer fitted with the paddle attachment on high speed. On low speed, mix in sugar until combined, then beat mixture on high speed until fluffy and smooth, about 3 minutes. Add salt to taste, if desired. Use immediately. Cook's Notes Natural peanut butter comes salted orunsalted; if necessary, add salt to taste. Rate it Print