Mix the cornstarch, flour, almonds and sugar, add the egg and 200 g butter in flakes and knead everything. Wrap the dough in foil and let it rest for 1 hour in the refrigerator.
Roll out the dough on a floured work surface and cut out round cookies. Place on a baking sheet lined with baking paper and bake at 200 ° for about 10 minutes (convection 180 °). Let the cookies cool down
Melt 100 g couverture and let it cool down to room temperature. Grate the marzipan mixture and beat it with the rest of the butter until frothy, stir in the couverture and put two cookies together with the cream. Decorate with chocolate couverture.