Add water, prunes and 1 cup of sugar to a saucepan and bring to boil. Reduce heat and simmer for about 10 minutes until the prunes are soft and have expanded in size. Strain out the water and set aside to cool.
Whisk egg yolks in a bowl with the remaining 1/2 cup of sugar then set aside.
Add cream and milk to a medium saucepan and heat until simmering. Remove from heat.
Slowly pour 1 cup of the milk into the yolks, all the while whisking until combined. Then pour the yolks slowly back into the saucepan of milk and lightly whisk. Continue heating until the mixture thickens, add a pinch of salt, then remove from heat.
Add the prunes and milk mixture to a blender. Process until you achieve the desired texture. I only blend for a couple of seconds because I like chunks of prune in the ice cream.
Cool the ice cream custard in the fridge for at least 3 hours, preferably overnight.
Churn in an ice cream maker as per manufacturer's instructions then scoop into a container and freeze for 2 hours.
Use a good quality salt, not the cheap table salt as it will tarnish the flavour of your ice cream.