For the dough of the blueberry and curd cake easy: separate the eggs and beat the snow. Slowly stir in the sugar and vanilla sugar and continue to stir. Carefully stir in the water/oil mixture and the yolks one by one.
Mix flour with baking powder and gently fold into the mixture. Spread onto a baking tray lined with baking paper.
For the curd mixture of blueberry-curd cake light: mix curd, sugar, vanilla and lemon juice and squirt with a piping bag in a grid on the dough.Line the interstices with blueberries.
Bake the cake at 180 degrees for about 20 minutes with hot air.