In large bowl, gently toss berries and 1/4 cup of the sugar. Cover; refrigerate 8 hours.
Heat oven to 450°F. Make pie crust as directed on box for One-Crust Baked Shell using 9-inch glass pie plate. Prick bottom and sides of crust with fork. Bake 7 to 9 minutes or until lightly browned. Cool completely on cooling rack, about 15 minutes.
Meanwhile, in small saucepan, stir together cornstarch and remaining 1 cup sugar; slowly stir in water and vanilla with whisk. Cook over medium heat 7 to 8 minutes, stirring constantly, until mixture thickens. In small bowl, mix gelatin and food color; stir into warm cornstarch mixture.
Drain blackberries; spoon into cooled baked shell. Pour glaze evenly over berries, pressing down gently with spoon to be sure all berries are covered. Refrigerate 2 hours before serving.