For the sponge cake, beat the eggs, 1 tablespoon cold water, 60 g sugar and 1 packet of vanilla sugar until fluffy. Mix flour and baking powder and sift over the mixture. Fold in carefully. Line the bottom of a springform pan (26 cm Ø) with baking paper.
Pour in the mixture and smooth it down. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for 12-15 minutes. Take out and let cool down.
Soak gelatine in cold water. Wash, halve and stone the nectarines. Cut 3 nectarines into small cubes. Mix cream cheese, crème fraîche, 1 packet of vanillin sugar and 70 g sugar, fold in the nectarine cubes.
Squeeze out the gelatine, dissolve and mix with 4 tablespoons of cream cheese mixture. Then stir into the rest of the cream and refrigerate for about 15 minutes.
Whip the cream until stiff. Coarsely grate white chocolate. Place a cake ring around the sponge cake. As soon as the cream cheese starts to gel, fold in the cream and 2/3 of the chocolate. Fill the cream onto the base, smooth it down and put it in a cool place for at least 2 hours.
Cut 3 nectarines into thin slices. Decorate the cake with twisted nectarine slices, white chocolate shavings and pistachio nuts.