Put flour, sugar, butter in flakes, vanilla pulp, salt and egg in a large bowl. Mix with the dough hooks of the hand mixer. Then work into crumbles with your hands. Grease a rectangular tart tin (26 cm x 19 cm x 3 cm). Clean and wash the rhubarb and cut it into pieces of approx. 2 cm width.
Fill the rhubarb and raspberries into the tin and spread crumbles on top. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 45 minutes on the bottom shelf. If necessary, cover with aluminium foil about 15 minutes before the end of the baking time. Remove from the oven, place on a rack and allow to cool slightly
Waiting time approx. 30 minutes