I'm writing on my iPod as usual and will post the link to the recipe later.
This is the I want Chocolate Cake Cake from Smitten Kitchen.
I had problems. My powdered Buttermilk didn't mix in well.
Although my butter was properly soft, my mixture of butter and dark brown sugar never got "fluffy" by any stretch of the imagination.
The cooking time was 18-22 minutes but the cake was floaty in the pan by the end of that time so I cooked it till a toothpick came out clean.
The cake is a single layer which is nice. It wasn't the nice nice moist cake I'm looking for. My buttermilk may have made all the difference.
The frosting is light and chocolatey and just right.
Not the chocolate cake I'm looking for, but nice with a glass of milk.