Place all ingredients into the blender. Blend until completely smooth.
Pour into a square baking dish and set in the freezer.
After 2 hours, scrape the surface of the granita. It will be like ice crystals. Keep scraping, every few hours, until you have a dish full of ice crystals, aka granita.
Store in the freezer. Let thaw a bit before serving. Re-scrape and serve plain or garnished with basil. Enjoy!