Sieve the flour, starch and baking powder into a bowl. Sift icing sugar and vanillin sugar over it and mix. Add eggs, oil and advocaat and mix with the whisk of the hand mixer to a smooth dough. Grease a springform pan (approx. 26 cm Ø). Add the dough and smooth it down.
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 1 hour. Take out and let cool in the tin for about 10 minutes. Remove from the tin and let cool on a cake rack. Coarsely chop the dark chocolate coating. Melt on a warm water bath. Stir in clarified butter. Chop and melt the white chocolate coating. Cover the cake with the dark chocolate coating. Pour the white couverture into a freezer bag, cut off a small corner and draw fine horizontal stripes over the dark couverture. Using a small wooden stick, draw vertical lines alternately from above and below at even intervals.
Stir in clarified butter. Chop and melt the white chocolate coating. Cover the cake with the dark chocolate coating. Pour the white couverture into a freezer bag, cut off a small corner and draw fine horizontal stripes over the dark couverture. Using a small wooden stick, draw vertical lines alternately from above and below at even intervals. Let the couverture dry for about 1 hour. Decorate with mint
waiting time approx. 2 hours