Preheat oven to 425°F/220°C. In a large bowl combine blueberries, sugar, lemon juice and zest (if using), cornstarch and salt. Let filling sit at room temperature.
Prepare the pie crust as instructed on the package. Fit the first dough into the pie plate and set aside. Roll out the second dough. Using a sharp knife or a pastry wheel, cut the dough into 8 even strips, 1” wide.
Fill reserved pie shell with blueberry mixture. Space 4 of the cut strips over the filling horizontally. Lay the other 4 strips lengthwise. Trim any overhang and pinch dough together to seal.
Bake 45-50 minutes. If crust browns quickly, cover the edges with a foil ring. Set on a wire rack to cool for 3-4 hours before serving.