In a small saucepan, bring sugar and 1 cup water to a simmer over medium low heat, stirring until sugar has dissolved. Remove from the heat. Stir in basil and let syrup stand for 15 minutes.
Stir together orange juice, vanilla and salt in a medium bowl. Pour basil syrup through a fine sieve into the orange juice mixture; discard basil.
Move mixture to a 9"x13" shallow nonreactive dish(glass is good). Chill in the freezer until edges are frozen, about 1 1/2 hours. Remove from freezer; scrape with a fork, pulling from the edges into center. Return to freezer. Repeat process every 30 minutes until the mix is the texture of shaved ice, about 4 hours. Spoon into serving bowls and garnish with basil sprigs. Enjoy!