100 g castor sugar
140 g liquid glucose
400 ml water
80 g basil leaves
4 limes (zest and juice)
Put the sugar, liquid glucose and water into a saucepan and stir over a medium-high heat until the sugar has dissolved. Add the lime zest then remove from the heat and leave to cool completely.
Wash the basil leaves and pat dry with kitchen paper.
Once the syrup has cooled, pour it into a blender and add the basil leaves and lime juice. Blitz until the basil leaves are finely ground and the syrup is bright green. You may wish to add more lime juice, tasting as you do and bearing in mind that the flavour will be muted when the mix is frozen.
Strain the mixture through a fine sieve or muslin cloth and pour into the bowl of an ice cream machine. Churn until soft set and transfer to a freezer-proof container, cover and freeze until firm.