Separate eggs for the floor. Beat the egg whites and 2 tablespoons of cold water with the whisks of the hand mixer until stiff. Add sugar, salt and vanillin sugar. Stir in egg yolk and lemon peel. Mix flour and baking powder, sieve onto the egg mixture and fold in carefully. Line the bottom of a springform pan (24 cm Ø) with baking paper. Add the sponge mixture, smooth it down and bake in the preheated oven (electric: 175 °C/ gas: level 2) for about 20 minutes.
Remove from the oven, remove from the edge of the springform pan and let it cool down on a grid. Remove the base completely from the mould. For the topping bring apple juice, wine, 75 ml water, lemon juice, sugar and lemon peel to the boil. Meanwhile wash 2 apples, peel, quarter, core, cut into slices and add to the boiling stock. Simmer at low heat for about 3 minutes. Remove from the stock with a skimmer and drain well. In the meantime, wash the remaining apples, core them with an apple corer and cut into slices. Add slices to the stock and cook over a low heat for 1-2 minutes. Remove from the brew with a skimmer and lay carefully on kitchen paper. Let it cool down. Soak the gelatine in cold water, squeeze it out and carefully melt it at low heat in a small pot. Add the gelatine drop by drop to the sea buckthorn puree while stirring constantly. Keep cold.
Add slices to the stock and cook over a low heat for 1-2 minutes. Remove from the brew with a skimmer and lay carefully on kitchen paper. Let it cool down. Soak the gelatine in cold water, squeeze it out and carefully melt it at low heat in a small pot. Add the gelatine drop by drop to the sea buckthorn puree while stirring constantly. Keep cold. In the meantime, whip cream until stiff. As soon as the sea buckthorn begins to gel, fold in the cream in portions. Place the cake base on a cake plate. Spread half of the sea buckthorn cream on the cake base, spread apple slices on top. Spread the cake with the remaining sea buckthorn cream all around. Put the cake in a cool place for about 10 minutes and then cover with the apple slices. Put the cake in a cool place for about 2 hours and serve it decorated with lemon balm as you like
In the meantime, whip cream until stiff. As soon as the sea buckthorn begins to gel, fold in the cream in portions. Place the cake base on a cake plate. Spread half of the sea buckthorn cream on the cake base, spread apple slices on top. Spread the cake with the remaining sea buckthorn cream all around. Put the cake in a cool place for about 10 minutes and then cover with the apple slices. Put the cake in a cool place for about 2 hours and serve it decorated with lemon balm as you like