The main thing is the decoration – my lame attempt at spider web is just a suggestion. Lots of sugar bats, ghosts, witchy sprinkles can be thrown onto it instead.
The cake is so easy to make it’s embarrassing – but excellent for the kids to be engaged. It's Nigella's recipe from 'Feast'.
For a grown-up non-Halloween version I would slice it, layer with apricot conserve or chocolate buttercream – and keep the dark chocolate topping. You can’t beat good ganache.