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-based pan, then add
the vanilla pod, scraping the seeds
into the mixture. Heat the creamy milk,
stirring occasionally, until almost boiling.
Add the mint leaves and stalks, cover
with a lid, and leave for 15 mins.
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-out pan and cook over a low heat,
stirring all the time, until lightly thickened
– about 3-4 mins. Take care it doesn’t
get too hot or it may curdle. Strain the
custard into a bowl and leave to cool,
stirring occasionally to prevent a skin
forming. Chill the custard until really cold
– it’s a good idea to leave it overnight.
Churn the custard in an ice-cream
machine until frozen. Add the chocolate
pieces just before it sets. If you don’t
have a machine, pour the custard into a
chilled container and freeze for 2-3 hrs
until the sides become icy. Whisk
thoroughly to break up any crystals,
then add the chocolate and freeze until
solid. Leave to soften in the fridge for
20-30 mins, then serve in bowls or cones.