Batter for cookies: Beat 3/4 sugar and egg yolks till thick and pale.
Whisk the egg whites in an electric mixer at high speed until soft peaks are formed.
Add 1/4 sugar and vanilla, still whisking until meringue forms stiff peaks.
Mix in half meringue in the egg yolk mixture, and carefully sift in flour and corn flour. Sift in the remaining meringue. Do not over mix.
2
Preheat the oven to 200C. Line the baking tray with waxed paper.
Spoon the mixture into a pastry (piping) bag fitted with a 1cm plain tip (nozzle) and pipe lines or rounds onto a cookie sheet leaving plenty of space in between to allow room for spreading.
Generously dust the tops with confectioner's sugar.
Bake for 12-15 minutes, or until lightly golden.
Let cool and remove them carefully from the paper.
3
Pastry cream: Mix the flour, cornstarch and sugar in a heavy bottomed non stick pan.
Lightly beat the egg yolks with 2 tablespoons of the milk, pour into the pan and mix well.
In another pan, bring the remaining milk to a boil and pour it gradually onto the egg and flour mixture stirring vigorously. Stir the mixture over medium heat until it comes to a boil. Reduce the heat and continue to cook, stirring constantly for about 7minutes or until the cream is thick and smooth.
4
Remove from the heat and stir in the cubed vanilla and butter.
*if the cream is too stiff, gradually stir in a little milk until the desired consistency is reached. If the cream is too thin, add 1 tsp more corn flour dissolved into two tablespoons of milk and continue cooking until it has thickened. If the cream is lumpy, strain it through a fine sieve or process in a blender for 1 minutes.
Press a piece of plastic wrap onto a surface to prevent from forming a skin and cool.
5
Chocolate frosting: In a heavy bottom sauce pan, pour the cream and bring to boil. Break the chocolate and add to the cream to melt. Cook for about 2 minutes. Cool slightly.
6
Putting it all together: Preheat the oven to 200C. Line a cookie sheet over the baking tray. Spoon the sponge cookie dough into a pastry bag fitted with a 1cm plain tip. Pipe 5cm rounds onto a prepared cookie sheet, spaced well apart. Sift a generous quantity of confectioner's sugar over each cookie and bake for about 10 minutes, or until lightly browned. Transfer to a wire rack and let cool. Sandwich pairs of cookies together with a thick layer of pastry cream and place on a serving dish. Spread the chocolate frosting over the tops. Store in the fridge till ready to use.