Makes 3 cups | Prep time: 10 minutes | Total time: 3 hours
- 3/4 cup xylitol
- 3/4 pound rhubarb, trimmed and cut into 1-inch pieces
- 3 tbsp. fresh lemon juice
- Bring the xylitol and 1 cup water to a boil in a 2-quart saucepan over high heat; cook, stirring, until the xylitol is dissolved, 1 to 2 minutes.
- Reduce the heat to medium-high and add the rhubarb; cook until tender, about 5 minutes.
- Add the lemon juice; cook 2 minutes more.
- Strain the mixture though a fine-mesh sieve, discarding solids.
- Pour into a 9-by-13-inch baking dish, cover with plastic wrap, and place in the freezer.
- Using the tines of a fork, stir the mixture every 30 minutes, scraping the edges and breaking up any ice chunks as the mixture freezes, until the granita is slushy and frozen, about 3 hours.
- Scoop into chilled serving glasses.