MAKES ABOUT 2 CUPS
½ cup (1 stick) unsalted butter, cut into ½-inch slices
⅔ cup unsweetened cocoa powder
3 cups confectioners’ sugar
3 tablespoons whole milk
1 teaspoon pure vanilla extract
In a medium saucepan, melt the butter over low heat. Stir in the cocoa powder and remove the pan from the heat. Add the confectioners’ sugar, milk, and vanilla and, using a handheld mixer, beat on medium-high speed until smooth and creamy. (Alternatively, if you do not want to use your mixer in the saucepan, transfer the butter mixture to a large bowl and proceed as directed.)