Guinness Chocolate Cake

I made this years ago, before I had a blog. Since then I have modified the recipe and completely changed the icing to make it into the cake I served for my menu project. The original cake is from Nigella Lawson's Feast. It's delicious, as delicious as mine, just a bit different. (I use more Guinness, but reduce it further so its slightly more pungent and bitter). Like I said, however, the main difference is the icing; hers is a relatively rich and thick cream cheese icing (thinned with milk) and mine is more light and fluffy with crème fraîche and heavy cream.