Coarsely chop the white couverture and melt it on a hot water bath. Leave to cool a little. Cream fat, sugar, vanillin sugar and salt. Stir in the eggs individually, alternating with the cornflour. Then add the white chocolate coating while stirring.
Mix flour and baking powder and stir in briefly. Pour the dough into a greased springform pan (26 cm Ø) sprinkled with flour and smooth it down. Bake in the preheated oven, 2nd shelf from below (electric oven: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 1 hour. Coarsely chop the dark chocolate coating and melt with the coconut oil on a hot water bath. Let the finished cake cool down. Using a wooden skewer or knitting needle, prick the surface of the cake several times until it reaches the bottom of the cake. Spread warm couverture, up to about 5 tablespoons, on the cake and let it cool down. Whip the cream until stiff. Remove the cake from the springform pan and lift it onto a cake plate. Spread the cream loosely on the cake.
Spread warm couverture, up to about 5 tablespoons, on the cake and let it cool down. Whip the cream until stiff. Remove the cake from the springform pan and lift it onto a cake plate. Spread the cream loosely on the cake. Warm the rest of the chocolate coating again slightly and spread it as a blob on the cream. Pull through with a fork like a marble. Serve dusted with icing sugar
On 16 pieces: