Put 150 g flour, icing sugar, butter in pieces, egg yolk and 2 tbsp. cold water into a mixing bowl and knead into a smooth shortcrust pastry. Press dough flat and wrap in foil and chill for approx. 20 minutes
Separate the eggs for the sponge cake. Beat the egg white and 3 tbsp. cold water until stiff, adding 100 g sugar. Stir in egg yolks. Mix 75 g flour, starch and baking powder, sieve onto the egg foam and fold in carefully. Put the mixture on a baking tray (approx. 32 x 38 cm) lined with baking paper and smooth it down. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 8-10 minutes. Take out the sponge cake and turn out on a damp tea towel sprinkled with sugar. Carefully peel off the baking paper and beat the moist cloth over the edges of the dough. Let the sponge cake cool down
Roll out the shortcrust pastry on a floured work surface until round (approx. 26 cm Ø), using a springform pan rim (approx. 26 cm Ø) to help. Prick the short pastry several times with a fork and place it on a baking tray lined with baking paper. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 15 minutes. Remove the short pastry base and let it cool down. Put the flaked almonds on a baking tray and bake in the oven at the same temperature for a few minutes until golden brown. Take out and let cool down
Soak gelatine in cold water. Wash and clean the strawberries and puree 300 g large strawberries. Mix cream cheese, quark, lemon juice, 1 packet of vanillin sugar, 125 g sugar and strawberry puree. Stir in the Prosecco at the end. Dissolve squeezed gelatine in a small pot. Stir in 4 tablespoons of strawberry cream, then stir into the rest of the cream. Chill for about 15 minutes until the cream starts to gel. Whip 200 g cream until stiff. Fold cream into the cream. Spread the cream evenly on the sponge cake. Put the sponge cake in a cool place for 10-20 minutes and let the cream get a little tighter. Cut the sponge crosswise into 5 equally wide strips. Place the short pastry on a cake plate. Carefully roll up the first strip and place it on the cut surface in the middle of the short pastry base. Wrap the remaining strips like a snail/ spiral. Place a cake ring firmly around the cake and chill for at least 4 hours, preferably overnight
Whip 200 g cream and 1 packet of vanilla sugar until stiff. Remove the cake from the cake ring and spread with cream. Press the almonds to the edge. Place the remaining strawberries tightly on the cake. Let the jam simmer slightly for about 1 minute and pass through a sieve. Spread the strawberries with the jam and chill for about 30 minutes until the jam is firm
Waiting time approx. 5 hours