Place the butter in a large mixing bowl. Add 2 C of the sugar and then the milk and vanilla.
beat until smooth and creamy, about 3 to 5 minutes. Gradually add the remaining sugar, 1 cup at a time, beating well after each addition (about 2 minutes), until the icing is thick enough to be of good spreading consistency. To your taste; you may or may not use all the sugar (though if you like magnolia cupcake icing, you will). If desired, add a few drops of food coloring and mix thoroughly. (Use and store the icing at room temperature because icing will set if chilled.) Icing can be stored in an airtight container for up to 3 days. (NOte from The Boo: It CAN be frozen and then brought back to room temp before spreading).