Chop 50 g dark chocolate coating. 1⁄8 l Heat coconut milk, add couverture and cocoa and stir until the couverture has melted. Leave to cool slightly. Grease a springform pan (26 cm Ø).
Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer).
Separate eggs. Beat the egg whites and 1 pinch of salt until stiff, chill. Cream 250 g butter, sugar and vanilla sugar with the whisks of the mixer. Stir in the egg yolks one after the other. Mix flour and baking powder and stir in alternately with 150 ml coconut milk briefly.
Cut the dough in half. Stir grated coconut and the remaining coconut milk into one half of the dough. Fold the chocolate coconut milk under the other. Fold one half of beaten egg white under each dough.
In the middle of the springform pan, put 2 tbsp. of the dark dough. Pour 2 tbsp. of the light-coloured dough in the middle. Continue until both types of dough are used up. Bake in a hot oven for 40-45 minutes. Remove from oven and let cool down.
Chop 150 g dark chocolate and milk chocolate. Melt together with coconut oil in a hot water bath. Remove the cake from the mould. Cover with approx. 3⁄4 chocolate coating, let it dry. If necessary, warm the rest of the couverture again slightly.
Spoon in circles on the cake with a spoon. Let it dry again.