Though this blackberry pie should be assembled and served the same day, you can get a head start by combining the berries and sugar and chilling them the night before.
1 1/2 cups fresh blackberries
1 1/4 cups sugar, divided
1/2 (15-ounce) package refrigerated piecrusts
3 tablespoons cornstarch
1 1/4 cups water
1/2 teaspoon vanilla extract
1 (3-ounce) package raspberry gelatin
4 drops blue liquid food coloring
Sweetened whipped cream (optional)
How to Make It
Gently toss berries and 1/4 cup sugar in a large bowl; cover and chill 8 hours. Drain.
Fit piecrust into a 9-inch pieplate according to package directions; fold edges under, and crimp. Prick bottom and sides of piecrust with a fork.
Bake at 450° for 7 to 9 minutes or until lightly browned.
Stir together cornstarch and remaining 1 cup sugar in a small saucepan; slowly whisk in 1 1/4 cups water and vanilla. Cook over medium heat, whisking constantly, 7 to 8 minutes or until mixture thickens.
Stir together raspberry gelatin and blue liquid food coloring in a small bowl; whisk into the warm cornstarch mixture.
Spoon blackberries into piecrust. Pour glaze evenly over berries, pressing down gently with a spoon to be sure all berries are coated. Chill 2 1/2 hours. Serve with whipped cream, if desired.