For the shortcrust pastry: 
Knead all ingredients to a smooth dough. Roll out and line a 24cm springform pan first with parchment paper, then with the shortcrust pastry. Bake at 160°C in the preheated oven for 10 minutes.For the sponge:
Separate the eggs. In a bowl whisk the egg yolks and the sugar until thickened and creamy. Whisk the egg whites until stiff, then fold the beaten egg white in the egg yolk mixture. Sieve the flour with the starch flour and cocoa powder on top, then gently fold in. Spoon the dough into a lined 24cm springform pan and bake in the preheated oven at 170°C for 30-35 minutes. When cold, cut into two equal rounds.

For the chocolate cream:
Carve the vanilla pod and scrap out the pulp. Bring the milk with 100g whipping cream, the vanilla pod and pulp to a boil. Remove from the heat, cover and allow to infuse. Beat the egg yolks and the sugar in a bain-marie until thickened. Remove the vanilla pod from the milk, then whisk the milk into the egg yolk mixture, still in the bain-marie. Whisk until the mixture is thick. Remove from the heat and stir in the grated chocolate. Allow to cool. Whisk the remaining whipping cream until stiff, then fold in.

To put the cake together:
Place a cake ring on a lined baking tray, put one of the sponge halves on the bottom and sprinkle with some tablespoons of vanilla syrup. Spread half of the chocolate cream on the sponge. Place the second sponge on top and sprinkle with syrup. Spread the remaining chocolate cream on top. Cover with the shortcrust pastry base and gently press down. Leave the cake to cool for 1 hour.

For the glaze: 
Soak the gelatin in cold water. Bring the water with sugar, cocoa powder and the single cream to a boil. Allow to boil for 3 minutes. Remove from the heat, then dissolve the squeezed out gelatin in the mixture. Allow the glaze to cool completely.

Turn over the cake onto a platter. Remove the cake ring and coat the cake with the chocolate glaze.