Place puff pastry slices next to each other on the work surface and allow to defrost. Place slices on top of each other and roll out to the size of a baking tray (approx. 33x39 cm). Place on a baking tray lined with baking paper. Prick several times with a fork and bake in the preheated oven (electric cooker: 200 °C/ gas: level 3) for about 15 minutes. Let them cool down.
Cut the puff pastry in three. Sort the berries. Whip cream until stiff. Mix mascarpone and quark. Stir in lemon juice and zest, vanilla sugar and sugar. Carefully fold in cream and berries. Spread a third of the puff pastry with half of the mascarpone cream. Cover with another third of puff pastry. Spread with the remaining cream and cover with the last layer of puff pastry.
Stir in lemon juice and zest, vanilla sugar and sugar. Carefully fold in cream and berries. Spread a third of the puff pastry with half of the mascarpone cream. Cover with another third of puff pastry. Spread with the remaining cream and cover with the last layer of puff pastry. Dust with icing sugar and cut into 8 pieces