Yield: 8 servings.
2 pounds fresh cantaloupe (about 2 melons), peeled and seeded
1 cup cold water
½ teaspoon lemon juice
1 teaspoon fresh orange juice
⅛ teaspoon salt
⅛ teaspoon white pepper (optional)
2 cups water
1 cup sugar
Fresh mint leaves (3 stems with leaves or 12 leaves, plus extra for garnish)
For the simple syrup: In a small saucepan, combine all ingredients. Bring to a simmer, stirring occasionally, until syrup slightly thickens. Remove syrup from heat and cool. Discard mint leaves. Refrigerate.
For the granita: Cut cantaloupe into bitesize chunks. Place in colander over a bowl and let drain. Transfer cantaloupe to a blender and add ½ cup simple syrup, water, lemon juice, orange juice, salt, and pepper. This may need to be done in 2 batches. Pulse on low power to blend fruit, then blend on high speed until smooth, about 1 minute. Add more water as needed to get a thick, slushy consistency. Pour into a 9 x 13-inch glass baking dish.
Place dish, uncovered, in the freezer until mixture barely begins to freeze around the edges, about 45 minutes. Mixture will still be slushy in the center.
Using a fork, lightly scrape the crystals from the edges of the dish into the center and mix thoroughly. Close freezer and chill until granita is nearly frozen, 30 to 40 more minutes. Scrape surface lightly with a fork as before, scraping the crystals loose. Repeat freezing and stirring with the fork 3 to 4 times until the granita is light, crystals are separate, and granita looks dry and fluffy, like a snow cone.
To serve, portion granita into chilled dessert cups or small bowls. Drizzle a teaspoon (or more) of mint simple syrup over granita and garnish with a sprig of fresh mint.