Make a batter from eggs, 150 g sugar, lemon zest, flour and baking powder. Spread this on a baking sheet and bake in the preheated oven at 170 ° C for approx. 10-15 minutes.
Soak the gelatine according to the instructions on the packet. Whip the cream. Sprinkle in 100 g sugar and 1 vanilla sugar and beat until stiff. Fold in natural yogurt. Squeeze out the gelatine, dissolve it and stir in. Spread the mixture on the sponge dough. Decorate the slices with the drained mandarins and refrigerate until ready to eat.