Make a batter from the dough ingredients and divide into two parts. Add part of the cocoa. Put the dough in a springform pan (26 cm) and bake each part separately at 160 ° C for about 30 minutes.
Cut each bottom once horizontally. Put the bases on top of each other alternately and spread 1 cup of sour cream mixed with 1 sachet of vanilla sugar on the base. The last layer is a floor. Then brush with chocolate or lemon icing.
Put the covered cake in the refrigerator for 3 days and let it steep. The cake tastes super juicy.