Chocolate Cloud Cake - it's cointreau-versial!

I made this amazing Nigella Lawson cake for Emily's birthday on Friday. It's a really intense chocolate cake containing no flour (so good for celiacs), with delicious Cointreau-flavoured cream on top. Really special and not difficult to make. You do need a springform cake tin and the skill for separating egg whites! Em has a picture of the result on her blog.