This outrageous pie is a base of crushed biscuits, a layer of caramel, a layer of whipped cream and then a scattering of crisp peppermint milk chocolate. It is incredibly rich and should probably be served in small spoonfuls, depending, of course, on your personal tastes. It makes me think of boarding school midnight feasts in books from the 1950s. You need to use chocolate bars with an apple-green crunchy filling, not a soft creamy centre. In South Africa we made this with ‘tennis’ biscuits, but digestives work just as well. It is possible to buy the condensed milk already boiled into caramel. If you can’t get it, you will have to simmer the tins in a large pot of water for about 3½ hours so the condensed milk turns nutty golden brown. Let the tins cool in the pot before removing and opening them — your condensed milk should be caramelized.