Roll out one disk of dough into a 13-inch circle, fitting it into a 9-inch pie pan. Refrigerate for 1 hour to chill.

Roll the second disk into a 12-inch circle, then cut into ten 1-inch strips for creating the beautiful lattice topping.

In a mixing bowl, gently combine the blueberries, lemon zest, lemon juice, granulated sugar, flour, and cinnamon. Toss until the berries are well-coated.

Pour the blueberry mixture into the prepared crust, mounding it slightly in the center to create an inviting shape.

Arrange the strips of dough over the blueberry filling in a crisscross pattern, overlapping them, and seal the edges by pinching together.

Brush the lattice top with the egg wash mixture for a lovely golden sheen, and sprinkle coarse sugar on top if desired.

Preheat your oven to 375°F and bake the pie for 50-60 minutes, or until the crust is golden brown and the filling bubbles enticingly.