½ cup of caster sugar
1.2 kg of watermelon rind removed and roughly chopped
2 teaspoons of lime juice
Place sugar and 1 cup cold water in a medium saucepan over low heat. Cook, stirring, for 3-4 minutes or until sugar is dissolved. Increase heat to high. Add watermelon. Bring to the boil. Reduce heat to medium. Simmer for 5 minutes.Cool for 10 minutes.
Place watermelon mixture in a food processor. Process until smooth. Strain into a large jug. Discard solids. Stir in lime juice. Pour mixture into an 18cm x 28cm slice pan. Freeze for 3 hours or until just beginning to freeze. Using a fork, flake mixture to break up ice crystals starting to form. Cover with foil. Freeze for 4 hours, flaking mixture every 1 hour, or until completely frozen. Serve.