Add cream, milk, sugar and coffee to a medium saucepan and, stirring frequently, heat until simmering. Don't allow to boil.
Whisk eggs in a separate bowl until pale in colour.
Slowly pour 1 cup of the heated milk mixture into the yolks all the while whisking; then pour back into the milk mixture while continuing to whisk.
Continue heating and stirring the milk mixture on a medium heat until it thickens and can coat the back of a spoon.
Remove from the heat and allow to cool for 5 minutes then pour through a strainer. Add to an airtight container and refrigerate for at least 3 hours. Preferably overnight.
Add ice cream base to your ice cream maker and churn following the manufacturer's instructions.
Once churned, freeze for at least 3 hours until hardened.
Notes
Reduce the coffee by 1/4 cup for a subtle tasting coffee ice cream. Add 1/4 cup for a stronger version.