Make the sponge cake. Preheat oven to 180°C and grease a 20 cm round springform pan with butter. Dust with flour and set aside.

Whip the eggs with the raw cane sugar for about ten minutes in a stand mixer or with your electric whisk, until white and thick. They'll be ready when lifting the beaters the batter will fall down making a ribbon.

Sift flour, potato starch, baking powder, a pinch of salt and vanilla seeds. Fold into the beaten eggs very gently with a spatula, making slow movements from the bottom upwards.

Scrape the batter into the baking pan and bake for about 30 minutes, until golden and springy.

Remove from the oven and after a few minutes unmould carefully the cake and let it cool completely on a wire rack.

Make the custard. Heat the milk over medium heat with the the vanilla bean until simmering. Remove from the heat.

Meanwhile, whisk the eggs with sugar and cornstarch in a saucepan until smooth and creamy.

Pour the hot milk in a thin stream into the beaten eggs and stir with a whisk to avoid eggs from curdling. Put the saucepan back on low heat and cook stirring constantly with a whisk for about 5 minutes, until thick and barely simmering.

Remove the custard from the heat and spoon it in equal parts into two bowls.

Add the chopped chocolate in one bowl and stir until completely melted.

Cover the custard and the chocolate spread with plastic wrap and let cool completely.

Make the syrup. Boil the water with the raw cane sugar and the orange zest until the sugar is completely dissolved. Let cool completely, then add the pomegranate juice.

Finally, make the cake. When the sponge cake is completely cold cut it lengthwise into three equal disks.

Brush first disc with the pomegranate syrup and spread generously with chocolate custard. Lay the second disc on top, brush again with the syrup and slather with custard. Close with the third disc.

Stack the cake in the fridge for at least half an hour.

Meanwhile, make the icing. Whisk the egg white with a fork and gradually add the icing sugar and the lemon juice until smooth and thick enough to cover the cake without slipping.

Spoon the icing on the cake and spread evenly with a spatula, letting it drop on the sides.

Decorate the cake with colourful sugar, fresh fruit or chocolate curls and let cool in the fridge a few hours before serving.