For the banana slices, beat egg whites with a little powdered sugar until stiff. Mix egg yolks with remaining powdered sugar and vanilla sugar.
After approx. 10 minutes, slowly drizzle in oil and water while continuing to mix. Stir in cocoa.
Mix in sifted flour with baking powder using a wooden spoon or whisk. Fold in the snow and spread on a greased baking tray.
Bake at 170 °C for approx. 25 minutes. Spread the cooled cake with jam and top with halved bananas.
For the cream, whip the patisserie cream until stiff and mix in the hazelnut cream briefly. Spread the cream on the bananas and sprinkle the banana slices with chocolate chips.
Preparation Tip:
Caution: treat the patisserie cream like whipped cream, i.e. do not mix too long to avoid butter.