Chocolate Sponge: Preheat oven to 180ºC Grease 23 cm round cake tin. Sift the flour and cocoa together; set aside. Using a wire whisk, mix eggs and sugar in a bowl set over a pan of hot water. Continue whisking until mixture is light and creamy. Remove from heat and whisk until cold. Gently fold the flour-cocoa mixture into egg mixture, then fold in melted butter. Pour batter into prepared cake tin. Bake for 30 minutes or until sponge springs back when tapped lightly in the center. Cool 10 minutes then turn out on rack to cool completely. Chocolate Meringue: Preheat oven to 160ºC and line a cookie sheet with parchment paper. By hand or with electric mixer beat egg whites until foamy. Add 1 cup sugar gradually and continue beating until egg whites are very stiff. Sift one third cup sugar and cocoa together; fold into the meringue mixture by hand. Spread meringue onto the cookie sheet. Bake at 160ºC until puffy. Turn off oven and leave meringue, with the door closed, until oven is cold and meringue is very dry. Meringue can be made in advance and stored in a dry place.