Whip the butter with the powdered sugar. Boil to thicken the milk, cocoa and 3.5 oz (100 g) grated chocolate. Once cool, add the milk mixture to the butter cream, while stirring. Once the mixture becomes homogeneous, add the two egg yolks one by one and the vanilla.
In a cake form, arrange a row of biscotti, which you've dipped briefly in the milk beforehand.
Smear with cream on top. Crumble meringues, macaroons and biscotti on top. Smear cream again and repeat this process until out of ingredients. Leave the cake in the refrigerator for one day.