Preheat your oven to 425°F (220°C).
In a mixing bowl, combine flour and cold butter. Use a pastry cutter or your hands to mix until it resembles coarse crumbs.
Add ice water, a tablespoon at a time, until the dough comes together. Divide the dough in half, wrap in plastic, and refrigerate for at least 30 minutes.
In another bowl, mix blueberries, sugar, cornstarch, lemon juice, lemon zest, and vanilla extract.
Roll out one half of the dough on a floured surface and fit it into a 9-inch pie dish. Pour the blueberry mixture into the crust and dot with butter pieces.
Roll out the second half of the dough and place it over the filling. Trim excess dough and crimp the edges to seal. Cut a few slits in the top crust to allow steam to escape.
Bake for 20 minutes, then reduce the oven temperature to 375°F (190°C) and bake for an additional 30 minutes, or until the crust is golden and the filling is bubbly.
Let the pie cool on a wire rack before serving.