Chocolate Whipped Cream Angel Food Cake

In a 1-1/2-qt. bowl, combine cream, cocoa and sugar; stir until well mixed. Refrigerate 8 hours or overnight. With an electric mixer, beat the cream mixture on low speed until frothy; increase speed to high and beat until stiff. Using a serrated knife, split cake into two horizontal layers. With the tines of a fork, remove a portion from the cut sides of the top and bottom layers to form a tunnel when the layers are place together. Frost entire cake with remaining whipped cream. Chill. Cake may be prepared a day ahead.