Heat oven to 350°F. Grease and flour 2 heart shaped pans or two 9 inch round baking pans. In small bowl, stir together cocoa and boiling water until smooth; set aside. In large bowl, beat butter, sugar and vanilla until fluffy; beat in eggs and cocoa mixture. Stir together flour, baking soda and salt; add alternately with buttermilk to butter mixture. Pour batter into prepared pans. Bake 30 to 35 minutes or until wooden pick inserted in center comes out clean. Cool 10 minutes; remove from pans to wire racks. Cool completely. Frost with