Mix flour with baking powder for the kneading dough. Add sugar, vanilla sugar, egg and margarine / butter. Knead the ingredients into a smooth dough and place in the refrigerator for about 30 minutes.
For the filling, stir together the sour cream, yoghurt, sugar, vanilla sugar, 5 egg yolks and pudding powder.
Beat the egg whites with the pinch of salt until stiff and fold into the sour cream mass.
Line a greased springform pan with the kneading dough and pull up an approx. 3cm high rim. Pour in the sour cream and bake in the preheated oven for 1 hour.
After about 15 minutes of baking, use a sharp knife to cut into the sour cream mass 1 cm from the edge. When the baking time is over, let the cake stand in the switched-off oven for 10 minutes, then remove it, remove it from the edge of the springform pan and let it cool for 1 hour with the springform pan on a wire rack. Then take it down and let it cool down completely.
For the topping, clean the rhubarb, peel it off and cut into small pieces approx. 1 cm. Steam the pieces together with the sugar in a saucepan until soft. Drain in a colander. Mix the icing powder with 250ml apple and currant spritzer, bring to the boil, stir in the rhubarb and use a tablespoon to spread on the cake. Let cool and decorate with cream if necessary.
Tips:
Instead of the apple and currant spritzer, only currant juice, cherry juice or apple juice can be used. If you don`t like all three variants, take 250ml of water instead of the juice, but then mix the icing with 2 tablespoons of sugar.
The Boss Kitchen editorial staff oversees content review, fact-checking, and recipe verification across the site. Published articles pass through the editorial team before going live, ensuring ingredient lists, techniques, cooking times, and nutritional claims hold up in a home kitchen. The team coordinates contributions across the site writers, handles reader corrections, and maintains consistency in measurement conventions, safety guidance, and dietary labeling. Posts under this byline typically represent team-reviewed reference material, site announcements, or editorial roundups rather than individual-author features, and they are held to the same sourcing standards as bylined recipe and product coverage.