Beat the softened butter until you get a fluffy cream. Add the sugar and hard-boiled egg yolks, which you have mashed in advance and do not stop stirring. Melt the chocolate with 1 tbsp water and add it to the main blend. Stir until you get a smooth cream.
Cut the wafers into oval layers or leave them in square shapes. Stick them together with the cream. At the very top, smooth out the cake with the cream. Decorate with almonds if desired and leave the cake for 12 hours in the refrigerator.