Line the bottom of a springform pan (26 cm Ø) with baking paper. Separate the eggs. Beat the egg whites, salt and 4 tbsp. cold water until stiff, adding 1 vanillin sugar and 100 g sugar. Beat the egg yolks one by one into the mixture. Sift the flour, starch and baking powder into it and fold in. Brush into the form. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/gas: level 2) for approx. 30 minutes. Cool down
Drain the tangerines, catching the juice. Soak gelatine in cold water. Mix yoghurt, 2 tbsp. mandarin juice, 1 vanilla sugar, 75 g sugar, lemon peel and juice. Squeeze the gelatine, dissolve over low heat. Stir in 4 tbsp. yoghurt, then stir into the rest of the yoghurt. Cool until it starts to gel (approx. 5 minutes)
Whip 400 g cream until stiff. Fold into the yoghurt. Halve the yoghurt cream. Fold the mandarins into one half. Cut the cake base 2x horizontally. Close the cake ring around the lower cake base. Spread yoghurt-tangerine cream on top. Place the 2nd cake base on top. Spread yoghurt cream on top. Place the cake base on top. Chill for about 5 hours.
Finely grind the pistachios in the universal chopper. Whip 200 g cream until stiff, pour in 1 vanilla sugar. Spread the cake with it. Sprinkle the pistachios on top, press lightly. If necessary, place a decoration template (see right) on top and dust with icing sugar. Remove stencil. Decorate the cake