Separate eggs. Beat egg whites and 3 tbsp. water until stiff. Stir in 100 g sugar and vanillin sugar. Stir in egg yolk. Mix flour, starch and baking powder, fold in
Pour into a springform pan (26 cm Ø) lined at the bottom with baking paper. Bake in a hot oven (electric cooker: 175 °C/circulating air: 150 °C/gas: level 2) for 25-30 minutes. Cooling down
Soak the gelatine. Drain the mandarins. Mix passion fruit juice with 50 g sugar and warm it up a little. Squeeze the gelatine and dissolve in the juice. Cool until the juice begins to gel
Whip the cream until stiff. Stir 2/3 of the gelled juice into the cream. Fold in tangerines. Add the rest of the juice as "streaks" to the cream
Cut through the bottom so that the top is thin and the bottom is thick. Crumble the thin bottom. Pile the cream on the thick base like a dome, spread the sponge cake crumbs on top and press down. Chill for about 3 hours. Dust with icing sugar