Bake pastry shells according to package directions.
In a saucepan, combine the apples, 2/3 cup apple juice and cinnamon. Bring to a boil. Reduce heat; simmer, uncovered, until apples are tender. Stir in brown sugar. Combine cornstarch and remaining juice until smooth. Stir into apples. Bring to a boil; cook and stir for 2 minutes or until thickened. Stir in walnuts. Split pastry shell; spoon apple mixture into pastry shells.