Preheat oven to 450 degrees F. Let frozen berries stand at room temperature for 15 minutes. Meanwhile, prepare pastry and line 9-inch pie plate. Line pastry with double thickness of foil. Bake 8 minutes. Remove foil. Bake 4 minutes more or until lightly browned. Cool on wire rack. Reduce oven to 350 degrees F.
In bowl combine sour cream, sugar, flour, and salt. Add blackberries and gently stir to combine. Spoon into prebaked crust. To prevent overbrowning, cover edge of pie with foil. Bake for 25 minutes (50 minutes for frozen berries). Remove foil. Bake 20 minutes more or until filling is bubbly and appears set. Cool on wire rack for 2 hours. Serve or cover and refrigerate. Makes 8 servings.
Pastry for a Single-Crust Pie
In a medium bowl stir together flour and salt. Using pastry blender, cut in shortening and butter until pieces are pea size.
Sprinkle 1 tablespoon of the water over part of the flour mixture; toss with a fork. Push moistened pastry to side of bowl. Repeat moistening flour mixture, using 1 tablespoon of the water at a time, until flour mixture is moistened. Gather flour mixture into a ball, kneading gently until it holds together.
On a lightly floured surface use your hands to slightly flatten pastry. Roll pastry from center to edges into a circle about 12 inches in diameter.
Wrap pastry circle around the rolling pin. Unroll into a 9-inch pie plate. Ease pastry into pie plate without stretching it.
Trim pastry to 1/2 inch beyond edge of pie plate. Fold under extra pastry even with the plate's edge. Crimp edge as desired. Do not prick pastry. Fill and bake as directed in recipes.