The mere sight of chocolate origin's cake really intrigued me. First question I would naturally ask would be how does the cross section looked like? This perfect looking with a layer of 'matt-choco' finishing glaze made me want to feel its smooth texture by tongue. I finally bought the 6 inch original cake to try.
Finally the revelation - Sponge, mousse, sponge, mousse and covered with a lovely coating of chocolate! The mousse was definitely rich, chocolatey and slightly cloying. I suggest you go with ice cream (like what I did) to reduce the cloying feeling. It was so filling but addictive!