For the moist curd cake, put the specified ingredients for the dough in a bowl. Quickly knead into a smooth dough and let rise, covered, for about 40 minutes until doubled.
Then roll out the dough to sheet size and place on the greased and floured baking sheet. Let rise again for about 20 to 25 minutes.
Meanwhile, for the topping, mix the egg yolks with sugar, butter, curd cheese, 2 cups of sour cream, vanilla sugar and lemon zest. Finally, beat the egg whites until stiff and gently fold in.
Spread this topping smoothly on the dough. Bake in the preheated oven at 180°C hot air for about 20-25 minutes (cover a bit if necessary so it doesn’t get too dark). Remove from the oven.
Immediately spread a cup of sour cream on the hot cake and sprinkle the moist curd cake generously with cinnamon.