Grapefruit Granita

Directions

1. 1
   COMBINE ALL INGREDIENTS in a deep-sided metal baking pan.
2. 2
   Freeze, uncovered, until mixture is nearly set, at least 4 hours, whisking mixture every hour.
3. 3
   Remove mixture from freezer and scrape surface with the tines of a fork until it is the texture of shaved ice.
4. 4
   (Mixture can be frozen overnight without whisking; remove from freezer in the morning, and let sit at room temperature about 10 minutes to allow it to slightly soften before scraping with a fork as instructed.)