What I'm giving you here is really more of a suggestion because the amount of Christmas pudding you'll have leftover will really depend on how greedy your guests were on Christmas day. But personally, I love Christmas pudding and I think it's almost worth having another pudding stashed away so you can make this as an after-Christmas treat.
Put a pan over a medium heat and crumble in your Christmas pudding. Squash it down a bit with a wooden spoon to help it heat up and get a bit crispy. Fry for about 4 to 5 minutes, stirring every so often so it doesn't catch.
In another small pan on a low heat, add your cranberry sauce with a splash of red or mulled wine. Stir in and cook for a few minutes until warmed through. Cook's Note: If your sauce is too tart for your liking, add 1 teaspoon or 2 of sugar. If you've made up a batch of my spiced sugar, then use that because it will be delicious with the cranberry.
Once your pudding is warm and slightly crispy and the sauce has heated up, divide 1/2 of your pudding evenly among your 4 glasses or bowls. Add a scoop of vanilla ice cream on top of the pudding, drizzle over your hot cranberry sauce, and a good sprinkling of toasted flaked almonds. Divide the remaining Christmas pudding among your glasses and layer again with ice cream, cranberry sauce, and flaked almonds. Finish the sundae off by grating over a bit of nice dark chocolate and dig in before the ice cream melts.