Make shortcrust pastry, leave to rest and then place in a springform pan (26 cm) and pull up one edge.
Mix the sour cream with milk, eggs, sugar and pudding powder well. Spread the sour cream evenly on the shortcrust pastry and bake for about 40 minutes at 175 degrees.
In the meantime, clean the rhubarb and cut into pieces approx. 2 cm wide and add sugar. Briefly sauté with the juice / wine and sugar. Drain the rhubarb well, collect the juice and allow to cool.
Distribute the rhubarb pieces decoratively on the cake.
Fill up the rhubarb stock to ¼ liter with water / wine / juice. Make the icing according to the instructions and distribute it over the cake.