This is a classic recipe I used to make when I was a kid. Something my mum taught me as a little girl. The basic recipe is a simple pound cake recipe and it can changed to make a chocolate cake or in this case a marble cake.
At home, we would just make the cake and as soon as it came out of the oven, cut it and start eating. We didn't have the luxury of any sort of icing.
As this was made at work, I added a mixture of butter and chocolate icing to give it a marble effect.