Whisk egg yolks and sugar until pale, set aside.
Add coriander and lime to a food processor or blender and process for a few seconds. The coriander doesn't need to be completely blended.
Heat cream and milk in a medium saucepan on a high heat until simmering, remove from heat.
Pour 1 cup of heated milk into egg yolks while whisking as quickly as possible.
Pour yolks into the saucepan of heated milk and return to a medium heat. Add coriander and lime. Stir frequently while heating until the mixture thickens and coats the back of a spoon.
Pour mixture into an airtight container and chill overnight.
Strain mixture then churn in an ice cream machine as per manufacturer's instructions.
Add to an airtight container and freeze for at leat 2 hours until hardened.