Put the milk, cream, dark chocolate, pepper and cinnamon in a saucepan and heat gently to boiling point. Stir until the chocolate has melted, then leave to one side to cool down.
In a large bowl, now combine well the sugar, egg white and the cocoa powder.
Now add the milk mixture carefully and whisk together until well combined and thick. You want to have a shiny, thick mixture.
In ice cream maker:
Pour the chocolate ice cream mixture into an ice cream maker and churn until ready.
Without ice cream maker:
Place the ice cream mixture into a freezer-safe container and put it in the freezer. Every 30 minutes, stir the mixture, until it is fully frozen. That will be after about 4 hours.