Break the chocolate into pieces.
Place the chocolate in a heavy-based saucepan and add the milk.
Place over medium heat and heat gently until smooth, while stirring constantly.
Remove the pan from the heat and set aside to cool slightly.
Place the sugar and egg yolks in a bowl and beat until pale and thick.
Stir in the cooled chocolate milk, then strain back into the pan.
Place the custard over a gentle heat and cook, while stirring constantly, until it thickens and coats the back of a wooden spoon.
Make sure the mixture doesn't boil or it will curdle.
Pour the mixture into a bowl and set aside to cool, stirring occasionally.
Whip the cream into soft peaks, and fold through the chocolate mixture.
Place the chocolate mixture into the ice cream machine and churn, according to the manufacturer’s instructions, until it’s frozen