I've been making this cake - coalition cake - since the Conservatives and Liberal Democrats became best friends after the General Election. I suppose the joke is wearing thin now and I'll have to go back to calling it plain old chocolate and vanilla marble cake but for now I like calling it coalition cake so that's what it is.
Although who is the chocolate and who is the vanilla? Perhaps Cameron is the chocolate, because he's rich (but not that dark) and Clegg is the vanilla? I don't think I have quite thought this one through but, whatever, the two mixes go together well in a tasty and satisfying way.
The recipe is your basic Madeira sponge mixture. I use Rachel Allen's recipe for her wonderful 'Bake' book, which is 225g (8oz) butter creamed with the same quantity of caster sugar until light and fluffy. Beat in four eggs and two teaspoons of vanilla extract and then fold in 225g (8oz) plain flour and two teaspoons of baking powder. Finally add 50ml (1.75 fl oz) milk and then put half of the mixture in spoonfuls around the prepared 20cm (8 in) cake tin. To the remaining mix add 50g (2oz) sifted cocoa powder and then dollop that into the tin with the vanilla mix.
Use a skewer or the tip of a knife to swirl the mixture around until marbled. Don't go mad - you're looking for a coalition with two distinct identities not one bland homogeneous whole. Politicians take note.
Bake at 180 degrees C (350 degrees F or gas mark 4) for 45 minutes, leave to cool in the tin for ten minutes, then turn out and leave on a wire rack until completely cold.
I like to ice mine and I use a basic vanilla butter icing. Use half and half unsalted and salted butter and use up to twice the amount of sugar than butter. I start with 100g of each (50g of each butter and 100g of sugar) then add an extra 50g of sugar if I think it needs it. Scrape the seeds out of a vanilla pod and add those too. Whip it all up with electric beaters until really fluffy and add a teaspoon of just boiled water at the end.
Smother the cold cake in the icing and serve in slices. Sadly no picture of this one. I have made it twice in recent weeks and twice it has been eaten before I have remembered to take its picture. I'll have to make it again...