The recipe for this Chilli and Orange Chocolate Cake comes from Sam Stern, and dates back to when he was a school boy. He's now graduated from University and has several cookery books to his name, specialising in recipes for school children and students.
The only change I make to the cake recipe is to use cayenne or pure chilli powder. I have tried pounding chilli flakes in a pestle and mortar and almost choked on the inhaled dust (even though I couldn't see it)! Rather than use either of Sam's recommended frostings, I add a smaller amount of a fudgy frosting made from one of Mary Berry's recipes - melt 90g plain chocolate with 30g butter, then beat in 1 tablespoon of golden syrup and 1 1/2 tablespoons of milk. Cool a little and pour on top of the cake, while it will still run, to cover the top easily. If you want it to run down the sides, to coat the cake completely, make double the amount and use straight away.
I added a few chocolate and sugar sprinkles, just to make it look a little more interesting, but decoration isn't really necessary.