In a large microwave-safe bowl, melt butter on high in 30-second intervals, stirring between each, until smooth (about 1½ minutes total). Let cool for 5 minutes. Add cocoa, whisking until smooth. Whisk in milk and vanilla until combined. Gradually add confectioners’ sugar, whisking until smooth. Use immediately.
Recipe by Paula Deen Magazine at https://pauladeenmagazine.com/mississippi-mud-brownies-recipe/