In a 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 Pam sprayed and floured 9 inch round baking pans. Bake at 350 degrees for 25-30 minutes or until a toothpick inserted near the center comes out clean. Cool for 10 minutes before removing from pans to wire racks.
In a mixing bowl, beat cream cheese until light. Add 1/2 c. powdered 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 cherries if desired.