These were my Random Acts of Cake cupcakes – marbled chocolate & vanilla cake with two-tone icing. The recipe is just a simple mod of my 1234 cake (add 1/2 cup cocoa & a little milk to half the batter), but the icing is a result of this video that I saw the other day (skip the bit about colouring the icing and watch the plastic wrap bit):

How did I not ever think of doing icing like this? Not only does it make cleanup a doddle, it makes it very easy to do multicolour icing – just pop two or more different-coloured icing sausages in the bag. Brilliant. You know you want to try it.