Preheat oven to 180 C (350 F). Grease a 23 cm (9 inch) spring form pan. Combine egg yolks, 2/3 of the sugar, vanilla sugar,hot water and flavouring concentrate in a mixing bowl. Beat at high speed until thick and creamy. Beat egg whites and remaining sugar to stiff peaks.
Sift together flour, cocoa, cornstarch and baking powder. Fold into egg yolk mixture gently, but thoroughly. Fold egg whites into egg yolk mixture gently. Turn batter into prepared pan. Bake on middle oven rack for 35-40 minutes. Remove from pan. Let cool completely.
Filling and Sprinkle – Slice the cake twice to make 3 layers. Sprinkle bottom layer with kirsch and cover with pie filling.
Combine whipping cream with Whip It and beat to stiff peaks. Spread 1/4 of the whipped cream over pie filling. Cover with second layer. Press tightly and sprinkle with kirsch. Spread 1/2 of remaining whipped cream on second layer. Cover with final layer. Se aside 60 ml (4 tbsp) of whipped cream for decoration.
Decoration – Spread sides and top of cake with remaining whipped cream. Sprinkle the top of the cake with shaved chocolate. Decorate with reserved whipped cream and maraschino cherries.