1. Put the sugar and water into a saucepan and bring to a simmer, stirring until the sugar has dissolved. Let cool. Stir in the lime juice and zest.

2. Remove the seeds from the melon and discard. Chop the flesh and puree in a food processor, adding in the sugar syrup at the end.

3. Pour into a shallow metal tray and freeze.

4. When ready to serve, scrape with a fork and pile into chilled glasses.