Preparation

Melt butter and water for the chocolate cake in a casserole.
Scrape out vanilla corn, mix them with sugar and beat the sugar with eggs until thick and creamy. Fold cocoa, baking powder and flour into the egg mixture alternately with the buttery water.
Line a springform pan with baking paper.
Pour batter into the pan and bake at 170 C / 340 F for 40 minutes.
Let the cake cool down completely (If you are in a hurry you can put it in the freezer).

Now make the blueberry jam.
Split the vanilla pod, scrape out the seeds and mash them with a teaspoonful of sugar to prevent them from lumping.
Pour blueberries, vanilla sugar, vanilla pod, sugar and lemon juice in a casserole and let it simmer for about 15 until the jam is nice and thick.
Remove the vanilla pod and blend the blueberry jam roughly.
Leave the jam to cool in the fridge.

Soak the gelatin sheets in water and start making the white chocolate mousse.
Heat up the whipping cream, but don’t let it boil. Remove the cream from the heat.
Chop the white chocolate, mix it with most of the cream and keep stirring until you have a shining, smooth chocolate blend.
Squeeze excess water from the gelatin and mix it with the remaining cream, while the cream is still warm.
Mix gelatin cream with the white chocolate mixture and pass it through a sieve.
Leave the chocolate mousse in the fridge for 1-2 hours to cool and settle.

Use a knife with a thin sharp blade to split the cake in two lengthwise.
Fold almost all the blueberry jam into the white chocolate mousse. Leaving just a couple of spoonfuls for the icing.
Spread the mousse over the bottom half of the chocolate cake.
Cover with the top half of the cake.
Boil a little water and mix it with the remaining blueberry jam.
Pass the runny jam through a sieve and mix it with powdered sugar.
Cover the cake in blueberry icing.
Chocolate blueberry cake should rest in the fridge for a couple of hours before it is ready to serve.