Whisk the custard, cream, condensed milk and liqueur (if using) together to soft peaks, then scrape this into a freezerproof container. Cover the surface with a sheet of baking parchment, then cover with the lid and freeze until firm, about 8 hrs.

Roughly tear the panettone into small pieces and toast in a dry pan over a medium-low heat for 3-4 mins, stirring often until golden. Leave to cool.

Warm the caramel sauce gently in a pan over a low heat. Layer scoops of the frozen custard with the crumbled mince pies, then top with the toasted panettone and warm caramel sauce. Any leftover ice cream will keep frozen for a week.