Preparation / Directions:
Place the watermelon chunks in a blender and puree until smooth. Strain through a fine-mesh sieve into a bowl. You should have 2 cups of puree. In a saucepan over high heat, combine the water and sugar. Heat, stirring, just until the sugar dissolves. Add the sugar syrup and lemon juice to the watermelon puree and stir well. Pour the mixture into a shallow 9-by-13-inch metal baking dish. Place, uncovered, in the freezer until ice crystals begin to form, 1 1/2 to 2 hours. Using a fork, stir to break up the mixture. Return to the freezer. Stir with a fork every 30 minutes to prevent the mixture from forming a solid mass. It should be evenly crystallized and like slush in another 2 hours. To serve, spoon or scoop the granita into chilled serving dishes.