Scold the milk, cream and sugar in a large saucepan. It should be around 80c.
Thoroughly bruise the mint and add it to the hot cream mix. Submerge it under the liquid and cover the pot with a lid. Let this mix infuse for at least 3 hours.
Strain the mix into a clean saucepan and discard the mint. At this point you can add a pinch of salt, this will help elevate the flavour of the chocolate.
In a separate bowl, whisk the egg yolks with an electric whisk or stand mixer till pale and fluffy/tripled in volume. Gently whisk the egg yolk into the infused cream mix and return the pan to the hob on a very gentle heat, constantly stirring with a rubber spatula till the mix thickens enough to coat the back of a spoon (83c).
Strain the mix through a sieve and into a bowl, with another bowl underneath full of ice and water to help it cool down quickly and safely.
Once cool, pour the mix into a tupperware container, with a sheet of parchment paper on top to prevent a skin forming. For many reasons, it is always better to leave an ice cream base to chill overnight before churning.
When ready, churn your ice cream.
While the ice cream is churning, use a knife to chop the chocolate into desired fragment size.
When the ice cream is 90% churned, scatter the pieces of chocolate into the mix.