Watermelon Granita

• 1¾ lb (750 g) peeled and seeded watermelon, diced
• 1-inch (2-cm) piece of fresh ginge

Combine all the ingredients in a blender and puree until smooth. Pour into a freezer-safe container. Cover the container and place it in the freezer for about 4 hours, beating it with a fork every hour, until it forms nice coarse ice crystals.

Scrape the granita with a fork before serving and spoon it into pretty, chilled coupes. Serve immediately; it melts quickly.