Minted Watermelon Granita

1 1/2 pounds seedless watermelon without the rind, cut into 1-inch dice (about 4 cups)

2 Tbsp sugar

1/4 cup mint leaves, minced

2 tsp finely grated lemon zest

Pinch of salt

1 Tbsp vodka

In a blender, puree the watermelon with the sugar until smooth. Stir in the mint, lemon zest, vodka and salt. Pour the puree into a container. About every hour while freezing (this takes about three hours) take out the granita and scrape it with a fork to keep it broken up. If there is any remaining, it is easily kept in the freezer. After being in the freezer over night it was necessary to let it sit on the counter to soften just a bit.