In the bowl of a stand mixer fitted with the whisk attachment, beat butter at medium speed until creamy. In a small bowl, sift together confectioners’ sugar, cocoa, and salt. Gradually add sugar mixture to butter, beating until combined. Gradually beat in buttermilk until mixture reaches a spreadable consistency. Use immediately.
Recipe by Paula Deen Magazine at https://pauladeenmagazine.com/frosted-cake-brownies-recipe/