Mix flour with baking powder and hazelnuts. Press a stiffener in the mItte. Add water, vanilla sugar, sugar and butter in pieces and knead everything together. Wrap in plastic wrap and let rest in the refrigerator for 2 hours.
Knead together marzipan and sifted powdered sugar. Roll out thinly between cling film. Allow chocolate icing to melt.
Roll out the dough on a floured work surface to a thickness of 2 mm and cut into biscuits. Place on a baking tray lined with parchment paper and bake in a heated oven at 175 degrees (gas: level 2) for about 8 minutes.
Cut out cookies of the same size from the marzipan and stick jelly on the cookies. Cover with chocolate icing and decorate each with a hazelnut.
Tip: Feel free to use better chocolate – the more delicious the result!