Clean, peel and chop the rhubarb the night before. Put in a bowl and sprinkle with sugar if you like. Chill overnight.
For the shortcrust pastry, mix the flour with the baking powder and sieve on the worktop. Add egg, sugar and butter and knead everything quickly. Wrap in foil and chill for about 30 minutes. Then roll out and put in a greased, floured springform pan.
For the filling, put the sour cream, sweet cream, eggs, vanilla pudding, vanilla sugar and sugar in a bowl and stir well (caution - it is liquid!). Pour the liquid off the rhubarb and pour the rhubarb onto the shortcrust pastry. Then pour the liquid cream and egg mixture over it.
Bake in the preheated oven at 160 ° C for about 1 hour and then leave to cool in the closed oven for about 25 minutes. Take out and let cool down.