From the St Louis Post-Dispatch Let's Eat section (4 servings)
2 cups frozen fruit
3/4 cup chilled orange, apple, or white grape juice (NOTE: For dark fruit, such as blackberries or blueberries, use orange juice. For peaches use apple juice or white grape juice.)
About 1 teaspoon lemon juice
2 tablespoons to 1/3 cup granulated sugar, to taste
Place fruit, juices and sugar into a food processor blender; puree until smooth. Taste; adjust lemon juice and sugar if necessary.