Stir first 3 ingredients in small bowl until sugar dissolves. Blend 3 cups strawberries in processor until smooth. Add sugar syrup and blend until combined.
Pour mixture into 13x9x2-inch nonstick metal baking pan. Freeze until icy around edges, about 25 minutes. Using fork, stir icy portions into middle of pan. Freeze until mixture is frozen, stirring edges into center every 20 to 30 minutes, about 1 1/2 hours. Using fork, scrape granita into flaky crystals. Cover tightly and freeze. (Can be made 1 day ahead. Keep frozen.) Scrape granita into bowls. Garnish with berries and serve.