Grease a springform pan (26 cm) well and sprinkle with breadcrumbs. Preheat the oven to 180 ° C.
First stir the eggs, sugar and vanilla sugar until frothy. Then stir in the cream and lemon flavor. Mix flour and baking powder, sieve into the sugar-cream mixture and stir. Finally stir in the orange lemonade. Transfer half of the dough into a separate bowl and stir in the cocoa powder well.
In the middle of the springform pan, alternate two tablespoons of light and dark batter. Important: do not spread the dough in the mold! Due to the liquid consistency, the dough runs independently.
Bake the cake for about 30-35 minutes. Make sure to do the chopstick test! After about 20 minutes, cover the cake with baking paper. Let the cake cool in the pan.
Then remove the edge of the springform pan and lift the cake onto a large plate or cake transporter. Dust the cake with powdered sugar if necessary.