Put the chocolate in a plastic bag, seal and freeze for at least 30 mins. Bash the frozen chocolate with a rolling pin until it shatters into small chunks inside the bag.
Pour the milk and cream into a medium heavy-
Strain the liquid, pressing the mint with a spatula to extract maximum flavour. Discard the leaves and stalks, and scoop out the vanilla pod.
Whisk the egg yolks and caster sugar until thick and pale – about 5 mins if you are using an electric whisk. Return the minty cream to a clean pan and bring back to almost boiling.
Pour half the hot liquid onto the egg and sugar mixture, whisking to combine everything before adding the remaining liquid. Return the custard to the rinsed-
Churn the custard in an ice-