Separate the egg. Beat the egg white until stiff, sprinkle with sugar and vanillin sugar. Add egg yolk and fold in. Mix flour, starch, baking powder and lemon zest and fold into the egg mixture.
Line the bottom of a springform pan (18 cm Ø) with baking paper and fill in the dough. Bake in a preheated oven (electric: 175 °C/ gas: level 2) for about 15 minutes. Remove the sponge cake base from the form and let it cool down.
Meanwhile, for the cream, peel and quarter apples, except for 1/2 apple, and remove the core. Cut the apples into pieces and stew them with half of the apple juice, 3 tablespoons of Calvados, lemon juice, cinnamon and vanilla sugar for about 5 minutes.
Puree with a chopping stick and let it cool down. Soak the sponge cake base with the remaining apple juice and 3 tablespoons of Calvados evenly and cover and allow to draw. Separate eggs and beat egg whites until stiff.
Cream egg yolk and sugar, add mascarpone and applesauce and stir in. Fold in the beaten egg white. Quarter the sponge cake and place it in a glass bowl with the tips facing upwards. Pour the cream into the bowl and let it stand in the fridge for about 2 hours.
Roast the flaked almonds in a dry pan and let them cool down. Cut the apple half with skin into 8 fine slices and steam in the remaining Calvados for about 3 minutes and let it cool down. Wash and drain the lemon balm.
Decorate the tiramisu with the apple slices, lemon balm leaves and almonds.