In a small saucepan, combine the water with the sugar. Stir to blend. Bring to a simmer over low heat, then transfer to a bowl to cool. Refrigerate.
Whisk all of the remaining ingredients in a small bowl, then stir in the syrup. Pour the mixture into a baking sheet and freeze until it hardens, about 3 to 4 hours.
When ready to serve, scrape the surface with the tines of a fork to remove the granita in large flakes. Spoon into serving glasses or bowls and serve.
Recipe courtesy Alex Guarnaschelli