Separate eggs. Beat egg whites, salt and vanilla sugar until stiff. Whip the egg yolks, 3 tablespoons of hot water and 120 g of sugar to a white cream. Mix flour, cornstarch and baking powder.
Pour the beaten egg white onto the egg yolk cream. Sift the flour mixture on top and fold in. Line the bottom of a springform pan (26 cm Ø) with baking paper. Fill in the dough and bake in a preheated oven (electric: 175 ° C / gas: level 2) for about 30 minutes.
Let it cool down on a cake rack. Cut the base twice horizontally. Mix plum puree, lemon juice and zest. Spread on two sponge cake bases. Whip 400 g cream, remaining sugar and cream setting agent until stiff.
Fold in 40 g pistachios. Spread the cream on the coated cake layers and place on top of each other. Place the remaining cake base on top. Whip remaining cream until stiff. Fill 1/3 into a piping bag with perforated nozzle.
Spread the rest of the cream all around the cake. Decorate with cream tuffs. Wash and stone the plums and cut them into slices. Spread on the cake. Chop the remaining pistachios very finely and decorate the cake with them.
Results in about 16 pieces.