Defrost puff pastry slices side by side on a floured work surface. Wash, clean and puree 100 g strawberries. Soak gelatine in cold water. Stir mascarpone, strawberry puree, sugar and 3 tbsp lemon juice until smooth. Melt the squeezed out gelatine in a small pot. Stir in 3 tbsp. cream, then stir into the rest of the cream. Whip cream until stiff and fold into the cream. Chill the cream until it begins to gel
Place puff pastry slices on top of each other and roll out rectangularly (approx. 30 x 49 cm). Cut the puff pastry into 3 pieces (approx. 13 x 30 cm each) and prick several times with a fork. Place 2 puff pastry slices next to each other on a baking tray lined with baking paper and bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for 20-25 minutes until golden brown. Remove the puff pastry bases from the oven and let them cool down. Bake the last puff pastry base in the same way
Wash, clean and slice 400 g strawberries. Spread approx. 1/3 of the cream on each of 2 puff pastry bases and cover them tightly with strawberry slices. Spread the rest of the cream thinly on the strawberries and layer the cakes on top of each other. Cover with the uncoated base
Mix 1 tablespoon lemon juice and icing sugar until smooth and drizzle over the top. Chill the puff pastry slices for about 2 hours, then cut into pieces and serve
waiting time approx. 3 hours