Source: Holiday Cookies
- 2 cups confectioners' sugar
- 4 tablespoons (1/2 stick) unsalted butter, melted and cooled
- 1/4 cup cocoa powder
- 1/4 cup milk
- 1/4 teaspoon pure vanilla extract
Place confectioners' sugar in a medium bowl. Whisk in butter and cocoa powder. Add milk and vanilla, and whisk until well combined.