Preheat your oven to 425°F (220°C). Roll out one pie crust on a lightly floured surface to fit a 9-inch pie dish. Transfer the crust to the dish and trim excess overhang.
Combine the thawed berries, sugar, lemon zest, and cornstarch in a mixing bowl. Mix well until the berries are evenly coated and the mixture begins to thicken slightly. Set aside to allow juices to meld.
Spoon the berry mixture into the prepared pie crust, spreading it evenly. Dot the filling with small pieces of cold butter to enhance flavor and achieve a shiny finish.
Unroll the second pie crust and place it over the filling. Trim excess crust and crimp the edges to seal the pie. Cut small slits in the top crust to allow steam to escape. Optional: brush the crust with an egg wash or milk for a golden color.
Place the pie on a baking sheet and bake in the preheated oven for 45 minutes, or until the crust is golden brown and the filling is bubbling and thickened. Check periodically to prevent overbrowning, covering edges if needed.
Remove from the oven and allow the pie to cool for at least 30 minutes. The filling will set slightly as it cools, resulting in a juicy but manageable slice with a crisp crust.
