Preheat the oven to 400°F (200°C)
Prepare a pie crust and place one crust in a 9-inch pie dish
In a bowl, combine blueberries, sugar, cornstarch, lemon juice, lemon zest, salt, and cinnamon
Toss gently until the blueberries are evenly coated
Pour the filling into the prepared pie crust
Dot the filling with small pieces of butter
Cover with the second crust or create a lattice top
Trim excess dough and crimp the edges
Cut a few slits in the top crust if using a full crust
Brush the top with egg wash or milk
Sprinkle with sugar if desired
Place the pie on a baking sheet
Bake for 20 minutes at 400°F (200°C)
Reduce the oven temperature to 350°F (175°C)
Bake for 35 to 45 minutes more, until the crust is golden and the filling is bubbling
Cover the edges with foil if they brown too quickly
Remove the pie from the oven
Cool completely before slicing
Serve at room temperature or chilled