Line the bottom of a springform pan (approx. 26 cm Ø) with baking paper. Separate 3 eggs. Beat 3 egg whites, 3 tbsp. cold water and 1 pinch of salt until stiff, adding sugar and vanilla sugar. Fold in 3 egg yolks one after the other.
Sift flour, starch and baking powder onto the egg mixture and fold in. Brush into the mould. Bake in the preheated oven (electric cooker: 175 °C/circulating air: 150 °C/gas: level 2) for approx. 25 minutes. Leave to cool in the mould.
Use a star template and several wooden skewers to cut into star shapes.
For the lemon balls, roast the almonds without fat and let them cool down. Crumble 3 biscuit remains (approx. 85 g). Knead with 2 tablespoons (60 g) Lemon Curd, 2 1⁄2 tablespoons lemon juice and liqueur first with a wooden spoon and then with your hands.
Press and form into 10 balls (cannot be rolled). Then roll in the almonds.
Cut the cake in half horizontally and spread 2 tablespoons of Lemon Curd on each cut surface. Crumble the remaining 2 cut-off sponge cake remains (approx. 50 g). Mix with 2 1⁄2 tbsp. lemon juice and 50 g sieved icing sugar.
Whip 250 g cream until stiff. Fold in the sponge crumbs, spread on the bottom cake layer, smooth it down. Cover with the upper cake base. Whip 100 g cream until stiff. Spread the cake rim with it and put the cake in a cool place for about 2 hours.
Sift 250 g icing sugar for the decoration. Whisk 1 egg white, icing sugar and 2 tbsp. lemon juice in a tall beaker with the whisk of the hand mixer until thick and creamy. Pour a little bit into a piping bag with a small perforated nozzle (7 mm Ø).
Spray the upper edge of the cake with it. Pour the rest of the mixture into a disposable piping bag and cut off a small corner at the bottom. Spray the icing ornaments onto the cake as desired and let it dry for about 30 minutes.
Serve the cake with the lemon balls.