- 1 1/4 cups lime sugar
- 1 1/2 cups granulated sugar
- 2 1/4 cups water
- 4 whole star anise (optional)
- 1 3/4 cups fresh lime juice (10 limes)
- 1/2 chilled watermelon, cut into slices or wedges
- Boil sugars, water, and star anise, stirring, until sugars are dissolved. Pour syrup through a fine sieve into a bowl, discarding solids. Cool syrup.
- Stir in lime juice.
- Freeze in a 13- by 9- by 2-inch glass dish, stirring occasionally with a fork, until liquid is frozen and granular, about 6 hours.
- Serve lime ice on watermelon.