1 cup creamy peanut butter
5 tablespoons unsalted butter or margarine, at room temperature
3/4 teaspoon pure vanilla extract
1/4 teaspoon kosher salt
1/4 cup heavy cream
Place the confectioners' sugar, peanut butter, butter, vanilla, and salt in the bowl of an electric mixer fitted with a paddle attachment. Mix on medium-low speed until creamy, scraping down the bowl with a rubber spatula as you work. Add the cream and beat on high speed until the mixture is light and smooth.