For the compote, peel and quarter apples and remove the core. Cut the fruit flesh into cubes. Put the diced apples, sugar, carved vanilla pod and lemon juice into a pot and boil down while stirring for about 10 minutes until the apples fall apart.
Stir apple juice and sauce powder until smooth. Bring the applesauce to the boil, stir in the sauce powder and allow to swell for approx. 5 minutes. Let the puree cool down. Separate the eggs for the sponge cake. Beat the egg whites, 4 tablespoons cold water and 1 pinch of salt until very stiff.
Add sugar. Stir in egg yolk. Mix flour, starch and baking powder and sift into the egg mixture. Fold in carefully. Line the bottom of a springform pan (26 cm Ø) with baking paper. Fill in sponge cake mixture and smooth it down.
Bake in the preheated oven (electric oven: 200 °C/ gas: level 3) for about 20 minutes. Remove from the tin and let cool on a cake rack. Whip cream until stiff, add sugar and a few drops of aromatic oil.
Cut the bottom twice crosswise. Spread half of the applesauce on the bottom layer. Spread a thin layer of cream on top and cover with the middle cake layer. Spread the rest of the applesauce (put some aside for the decoration) on top, again spread a layer of cream on top and cover with the third base.
Spread the cake with cream all around. Spray the remaining cream decoratively onto the cake with a piping bag. Pour apple sauce in the middle of the cake. Sprinkle the surface and the edge of the cake with brittle.
Decorate as desired with mint leaves. Makes about 12 pieces.