Blend the basil leaves with the sugar in a food processor, then combine with the other ingredients. Pour the mixture into an ice cream maker and churn for about 20 minutes. Either serve immediately or pack into plastic containers for the freezer (allow the ice cream to sit for 15 minutes in the fridge before serving).
This has a wonderful flavour if it is eaten as fresh as possible – don't store it for too long in the freezer.
For the raspberry coulis...
Heat the fruit, with a little water and a sprinkling of sugar in a small saucepan over medium heat, stirring from time to time, until the sugar dissolves completely, about 5 minutes. Mash with a potato masher and serve!