Separate eggs. Beat egg white and salt until stiff. Sprinkle 1 packet of vanilla sugar and sugar. Carefully stir in the egg yolks. Mix flour, starch and baking powder, sieve onto the egg mixture and fold in. Spread the dough on a baking tray (32x38 cm) lined with baking paper.
Bake in the preheated oven (electric cooker 175 °C/ convection oven: not suitable/ gas: level 2) for 15 minutes. Turn out the sponge cake onto a damp tea towel. Peel off baking paper and cover with a damp tea towel. Peel, quarter and core apples, cut into thin slices and sprinkle with lemon juice. Steam apple slices in a little water for 3 minutes, remove and drain on kitchen paper. Soak gelatine in cold water. Whip cream and 1 sachet of vanilla sugar until stiff. Stir the poppy seed bake until smooth, fold in the cream. Squeeze the gelatine, dissolve and stir into the poppy seed cream. Spread the poppy seed cream on the sponge cake. Spread apple slices on top and roll up into a roll.
Soak gelatine in cold water. Whip cream and 1 sachet of vanilla sugar until stiff. Stir the poppy seed bake until smooth, fold in the cream. Squeeze the gelatine, dissolve and stir into the poppy seed cream. Spread the poppy seed cream on the sponge cake. Spread apple slices on top and roll up into a roll. Chill the sponge roll for 1 hour. Dust the sponge roll with icing sugar, cut into pieces and decorate with apple and lemon balm
Waiting time approx. 1 hour