In a small bowl, stir together the cake flour, sugar and baking powder.
In a bowl, whisk together the oil, whole eggs and ¼ cup of water and stir in the flour mixture into the oil mixture until the batter is smooth.
Beat the egg whites with the cream of tartar until they hold stiff peaks.
Stir ¼ of the whites into the batter to lighten and then fold in the remaining whites.
Pour batter into prepared pan and bake in the middle of the preheated oven for 20-30 minutes, or until a tester comes out clean.
Remove cake and let cool.
For pastry cream: Scald the milk with the vanilla bean.
Scrape the seeds into the milk and discard bean (or rinse it, let it dry and plant it into a sealed jar of sugar. In time youll have sugar with a vanilla fragrance.) In a bowl, whisk together 1/3 cup of sugar, flour and egg yolks.
Whisk the hot milk into the yolk mixture, a little at a time, and whisk for 1 minute.
Pour into the pan and bring custard to the boil, whisking constantly, for 1-2 minutes, o until it is thickened.
Let cool, uncovered, and chill it, placing a piece of plastic wrap directly on the surface of the hot custard to prevent a skin from forming.
Beat the cream with the remaining 2 tblsps sugar until it holds stiff peaks.
Fold 1 cup of the whipped cream into the pastry cream, reserving remainder, and fold in 1 cup of coconut into the pastry cream as well.
Make chocolate sauce: Simmer the milk with the chocolate, stirring, until the chocolate is melted.
Add the cream, butter and sugar and simmer, stirring, until smooth and slightly thickened.
Keep sauce warm, covered.
Cut cake horizontally into 3 layers with a serrated knife.
Spread ½ of pastry cream on top of bottom layer and top with second layer.
Spread remaining pastry cream on top of second layer and top with third layer, cut side down.
Spread whipped cream on top and side of cake and sprinkle with coconut.