In mixing bowl, cream butter and sugar. Add eggs, one at a time, beating well after each addition. Beat in vanilla. In a bowl, whisk cocoa and water until smooth; stir in buttermilk.
Sift together flour, baking soda, baking powder and salt; add to creamed mixture alternately with cocoa mixture. Beat until smooth.
Pour into three greased and floured 9 inch round cake pans. Bake at 350 for 25-30 minutes or until a toothpick comes out clean. Cool for 10 minutes before removing from pans to wire racks.
For frosting, in mixing bowl, beat cream cheese until light. Add 1/2 cup confectioners sugar; mix well. Add the vanilla, cream and remaining sugar; beat until frosting reaches desired consistency. Place one cooled cake layer on a serving plate; spread with a third of the frosting. Repeat layers twice. Garnish with maraschino cheeries and mint if desired. Refrigerate leftovers.