Wash the rhubarb, cut into small pieces and stir with the sugar.
Quickly work all the ingredients for the crumble with your hands into crumbs.
Put one half of the streusel in a greased springform pan, press down on the base, pull up one edge and place in the refrigerator for 15 minutes.
For the quark filling, stir all the ingredients with a whisk until smooth, pour into the springform pan and smooth out.
Shake off the rhubarb.
Distribute the rhubarb pieces on the quark mixture and cover with the remaining crumble.
Bake in a preheated oven at 170 ° top / bottom heat for 45 - 55 minutes until golden yellow.
After baking, open the oven door a crack and then let the cake cool down completely.
Remove the rhubarb cake from the springform pan before serving and sprinkle with a little powdered sugar.