OK, so you've made MarsLady's lemon drizzle cake successfully.... Leave out the lemon, add 2 tablespoons of cocoa powder and add some extra milk to make the consistency right. Throw in a 200g bar of plain chocolate which youve chopped into chunks. Bake as per lemon drizzle.
Make a chocolate syrup with 2 teaspoons cocoa, 25oml water (although I don't think you need nearly this much) and 200g caster sugar. Bung in a pan and boil for about 5 minutes or until it's reduced to a more syrupy consistencey. Prick warm cake witha fork/kebab skewer and carefully drizzle over so it soaks in. Or just ice it with chocolate icing!!
Trust me (and MarsLady, after all it was her idea)