Let the puff pastry slices thaw for about 10 minutes according to the package instructions. Roll out 3 slices on top of each other and on a floured work surface to form a square (approx. 29 x 29 cm). Place the dough on a baking tray lined with baking paper and let it rest for about 5 minutes
Place an opened springform ring (from a springform pan 26 cm Ø) on the dough and cut out a circle (28 cm Ø). Prick the pastry base several times with a wooden skewer. Mix the egg yolk and about 1/2 tsp. cold water. Spread a thin layer on the base. Bake in the preheated oven 2nd shelf from below (electric oven: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for 10-12 minutes until golden brown. Remove and let cool off
Roll out the remaining slices of dough in the same way, place them on a second baking tray lined with baking paper and let them rest for 5 minutes. Cut out a circle (approx. 28 cm Ø) with the edge of the springform pan, prick it several times and brush it with egg yolk. Cut the dough into 12 cake pieces. Bake in the preheated oven 2nd shelf from below (electric oven: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for 10-12 minutes. Take out and let cool down
Wash the lemon thoroughly, dab dry and finely grate the peel. Squeeze 1/2 lemon. Mix mascarpone, quark, sugar, vanillin sugar, grated lemon peel and 1-2 tbsp. lemon juice with the whisks of the hand mixer until smooth
Place the whole puff pastry base on a cake plate and spread with raspberry jam. Spread lemon mascarpone cream on top and smooth it down. Chill the cake for about 15 minutes
Cut a stencil from cardboard into a cake piece form and cut out an egg at the broad end (cakes 13 cm long, short side approx. 6.5 cm long; egg approx. 4.5 cm long, 2.5 cm wide). Dust one icing sugar egg after the other on each puff pastry fan using the template. Place the fan on the cake shortly before serving
Waiting time approx. 45 minutes