Place the puff pastry slice next to each other and defrost. Place 3 slices on top of each other and roll out on a floured work surface and cut into circles (28 cm Ø).
Let the dough rest in cold for 5 minutes. Line a baking tray with baking paper. Bake the dough circles one after the other in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 20 minutes. Cool down on cake racks.
Whip the cream until stiff and allow the vanilla sugar to trickle in. Stir the jam until smooth and put 2 tablespoons aside. Spread the base with jam and spread the cream evenly on top. Place the cake bases on top of each other and decorate the surface of the cake with the rest of the jam.
Serve immediately.