Line a baking tray (approx. 35 x 40 cm) with baking paper. Separate the eggs. Beat the egg whites, 4 tbsp. cold water and salt until stiff, sprinkle in 150 g sugar and vanillin sugar. Beat the egg yolks separately into the mixture. Sift flour, starch and baking powder into the mixture and fold in. Spread on the baking tray. Bake in the preheated oven (electric cooker: 200 °C/circulating air: 175 °C/gas: level 3) for about 12 minutes. Turn out onto a damp tea towel. Remove baking paper immediately. Let the sponge cake cool down
Cut the sponge cake in half crosswise and place on 2 trays. Place one rail made of multi-folded aluminium foil (approx. 6 cm wide) around both plates. Soak gelatine in cold water. Sort and wash the berries. Strip currants from the panicles
Mix yoghurt, 150 g sugar, lemon peel and juice. Squeeze out the gelatine and dissolve over a mild heat. Stir in 4 tablespoons of cream and then stir into the rest of the cream. Chill for about 10 minutes until it starts to gel. Whip cream until stiff, fold in. Spread on the plates. Press the berries lightly onto them. Chill for at least 7 hours.
Mix casting powder and 4 tablespoons of sugar. Stir in apple juice and 1/4 l water and bring to the boil while stirring. Spread on the berries. Chill for about 1 hour.