Preheat your oven to 375°F (190°C).
In a mixing bowl, combine flour and salt. Cut in cold butter until the mixture resembles coarse crumbs. Gradually add ice water, mixing until dough forms a ball. Divide dough in half, shape into discs, and refrigerate for 30 minutes.
Roll out one disc of dough on a floured surface to fit a 9-inch pie dish. Transfer dough to pie dish.
In another bowl, combine blackberries, sugar, cornstarch, lemon juice, lemon zest, and vanilla extract. Pour mixture into pie crust.
Roll out the second disc of dough and place over the filling. Trim, seal, and flute edges. Cut slits in the top crust to allow steam to escape.
Bake in preheated oven for 45 minutes or until crust is golden brown and filling is bubbly. Cool on a wire rack before serving.