With a handheld or stand mixer fitted with a paddle attachment, beat the butter on medium speed until creamy, about 2 minutes. Add confectioners’ sugar, cocoa powder, and milk. Beat on low speed for 30 seconds, then add the peanut butter, vanilla extract, and salt. Beat on medium-high speed for 2 minutes until combined. Add 1/4 cup more confectioners’ sugar if frosting is too thin or another 1-2 Tablespoons of cream/milk if frosting is too thick. Taste. Add a spoonful of extra peanut butter or a pinch of salt if desired.

Frost your cake, cupcake, or confection however you’d like. In the pictured cupcakes, I piped a basic tall swirl using (affiliate link) Ateco 849 piping tip.

Use immediately or cover tightly and store for up to 1 week in the refrigerator or up to 3 months in the freezer. After freezing, thaw in the refrigerator then beat the frosting on medium speed for a few seconds so it’s creamy again. After thawing or refrigerating, beating in a splash of heavy cream or milk will help thin the frosting out again, if needed.