Defrost 2 pastry sheets on top of each other. Then roll out on a lightly floured work surface to a round dough base (26 cm Ø). Brush all bases with egg yolk, prick several times with a fork and sprinkle with sugar crystals.
Cut one of the bases into 12 cake pieces. Place on baking trays lined with baking paper. Bake in the preheated oven (electric: 200 °C/ gas: level 3) for about 15 minutes. Then let it cool down.
Whip the cream until stiff. Allow the cream setting agent and vanillin sugar to trickle in. Spread 2 cake layers each with plum puree. Spread the cream on top. Place pieces of puff pastry all around on top. Makes about 12 pieces.