Step 1 Put the sugar, water and zest in a medium saucepan and heat until the sugar dissolves.
Step 2 Stir in the basil and the orange and lemon juices. Allow the mixture to infuse for at least 1 hour or overnight.
Step 3Freeze the mixture and follow the four-time scraping and freezing process described in the star anise and grapefruit granita recipe.