How to make
For the layers, melt the dark chocolate and cubes of butter in a water bath. Remove from the heat, add the sugar and stir until homogeneous.
Once the mixture cools, add the eggs with the flour and lemon zest, while stirring nonstop. Pour the mixture into a cake form with baking paper and bake at 370°F (190 °C) for 30 min. Once the layer cools, cut it into 3 separate layers using a thread.
For the cream, add the powdered sugar to the melted butter and beat well. Next, add the yolks and stir once again until homogeneous. Also add the chocolate which you've melted in a water bath and cooled ahead of time. Flavor with the vanilla.
Put 1 layer into a suitable platter and smear it with half the cream, then place the 2nd layer, the rest of the cream and the final layer.
For the glaze, melt the 2 types of chocolate separately in a water bath, add a little oil to them and stir. Pour the melted dark chocolate over the cake.
Pour the white one in several places on top and make random shapes using a toothpick. Decorate with chocolate sprinkles on the sides. Sprinkle with lemon zest on top.
Leave the cake in the fridge to harden.