This recipe is designed for a shape with a diameter of 26 cm!
Clean, peel and cut the rhubarb and apples into small cubes. Put in a bowl and mix with sugar, custard powder and juice.
Preheat the oven to 180 ° C.
For the streusel, place the flour, baking powder, sugar, vanilla sugar, salt, the egg and the warmed butter in a second bowl and work it into a crumbly mixture. Grease the pie form and press two thirds of the crumble into it so that the base is covered and an approx. 1 cm high rim can be formed. Put the apple and rhubarb mix on top. Scatter the remaining crumble and flaked almonds over the top.