Jaffa Cake...Cake

I'm going to attempt to make a giant jaffa cake this weekend.  I have no idea what I'm doing.  Hope it works.  This could be the best cake ever...or the worst.  I don't have a recipe, I'm going to make it up as I go.

Wish the family luck, they're the ones who have to eat it


EDIT:
I can't vouch for this personally cos I don't eat chocolate but apparently it was the best cake ever.