Beat yolks, powdered sugar, oil and water until foamy.
Beat the egg whites with a pinch of salt until stiff.
Sift the baking powder into the flour and fold both into the yolk mixture. Finally, carefully mix in the stiff snow.
Spread the mixture on a baking tray lined with baking paper.
For the curd mixture, whisk the curd, yolks, powdered sugar and a packet of vanilla sugar until fluffy.
Beat the egg whites until stiff and fold into the curd mixture.
Pipe the curd mixture in a lattice shape onto the sponge mixture and bake the curd lattice cake for 35 minutes at approx. 180 °C.