Preheat oven to 350°F. Line a jelly roll pan with wax paper
(pan should be appproximately 10 x 15 x 1 or 11 x 17 x 1). Whisk together cocoa, sugar and boiling water. Cool mixture to lukewarm. Prepare angel food cake mix per package directions, using 1 1/4 cup water and adding cocoa mixture. Spread batter evenly into prepared jelly−roll pan. Bake 20 minutes or until top looks dry. Invert onto a large wire rack. Remove the pan and wax paper; cool. Slice cake into three equal parts. Start with cake, top with cherry pie filling, then top that with more cake and more pie filling and end with cake layer. Frost and decorate with chocolate shavings.