Preheat your oven to 425°F (220°C).

Roll out your pie crusts and fit one into the pie dish.

In a mixing bowl, combine the blackberries, sugar, cornstarch, lemon juice, vanilla extract, and salt.

Pour the blackberry mixture into the prepared crust.

Dot the filling with small pieces of butter.

Cover with the second pie crust, crimp the edges to seal, and cut slits in the top crust.

Bake in the preheated oven for 45 minutes until the crust is golden and the filling is bubbling.

Let the pie cool for at least 30 minutes before slicing.