Separate the eggs. Beat yolks, lemon zest and powdered sugar until foamy.
Add oil and water alternately.
Beat egg whites with fine crystal sugar until firm and add to yolk mixture.
Mix and sift flour and starch and fold in at the end.
Pour the mixture into a 20 cm cake pan or ring with baking paper and bake in a preheated oven at 170 degrees hot air for 35 minutes.
Allow to cool. Do not forget to test the cake.
For the cream, mix curd, yogurt, lemon juice and sugar. Soak gelatine leaves in cold water.
Whip GUMA Pâtisserie cream until stiff.
Add the pâtisserie cream to the curd mixture and mix well.
Squeeze out the gelatine, heat in a saucepan or microwave and stir briskly into the cream.
Finally, add the grated couverture to the cream. Refrigerate for 30 minutes.
Cut the cake in half crosswise. Place one cake layer in a cake ring, spread half of the cream on top and cover with the second layer. Pour the remaining cream (except for 3 tablespoons needed for lining) on top and refrigerate for at least 2h.
Remove the cake ring, decorate with the remaining cream, chocolate and lemon slices and serve.