Step 1: Make the Pie Crust

In a large mixing bowl, whisk together the flour, sugar, and salt. Add the cold butter cubes and use a pastry cutter, two forks, or your fingertips to work the butter into the flour until the mixture resembles coarse crumbs with some pea-sized butter pieces remaining. This texture is crucial for flakiness—don’t overwork it into fine powder. Drizzle in ice water 1 tablespoon at a time, gently mixing with a fork after each addition. Add just enough water until the dough begins to clump together when pressed. You might not need all the water. Gather the dough together, divide it into two discs (one slightly larger than the other), wrap each tightly in plastic wrap, and refrigerate for at least 2 hours or up to 3 days. Cold dough is essential for flaky crust.

Step 2: Prepare the Filling

In a medium bowl, gently combine the blueberries, sugar, cornstarch, lemon juice, lemon zest (if using), cinnamon (if using), and salt. Toss gently to coat the berries evenly without breaking them. Let the mixture sit for 15-20 minutes while you roll out the crust. This allows the berries to release some juice and the cornstarch to begin absorbing liquid. If using frozen berries, don’t thaw them—use them straight from the freezer.

Step 3: Roll Out Bottom Crust

Remove the larger disc of dough from the refrigerator and let it sit at room temperature for 5-10 minutes to soften slightly (this prevents cracking). On a lightly floured surface or between two sheets of parchment paper, roll the dough into a 12-inch circle about ⅛ inch thick. Roll from the center outward, rotating the dough frequently to maintain an even circle. Carefully transfer the dough to your 9-inch pie dish by rolling it around your rolling pin, then unrolling it over the dish. Gently press it into the bottom and sides without stretching (stretched dough shrinks during baking). Trim the overhang to about 1 inch beyond the rim. Place in refrigerator while you roll the top crust.

Step 4: Roll Out Top Crust

Roll the second disc of dough into an 11-inch circle using the same technique. You can leave it as a full circle for a traditional double-crust pie, or cut it into strips for a lattice top. For a lattice, cut the dough into strips about ¾ to 1 inch wide using a sharp knife or pastry wheel. Place the rolled-out top crust or lattice strips on a parchment-lined baking sheet and refrigerate until ready to use.

Step 5: Assemble the Pie

Preheat your oven to 425°F (220°C). Remove the bottom crust from refrigerator. Pour the blueberry filling into the prepared crust, spreading it evenly. Dot the top of the filling with the 2 tablespoons of butter pieces—this adds richness. If making a double-crust pie, place the top crust over the filling, trim excess dough, and crimp the edges together decoratively by pressing with a fork or pinching with your fingers. Cut several slits in the top crust to allow steam to escape. If making a lattice, weave the strips over the filling, trim excess, and crimp edges. Brush the entire top crust with egg wash and sprinkle generously with coarse sugar.

Step 6: Bake the Pie

Place the pie on a baking sheet (to catch any drips) on the lowest oven rack. Bake at 425°F for 20 minutes to set the crust. Then reduce temperature to 375°F (190°C) and continue baking for 35-45 minutes more until the crust is deep golden brown and filling is bubbling vigorously through the vents or lattice. The filling must bubble throughout (not just at the edges) to ensure the cornstarch has fully activated and thickened properly. If the crust edges brown too quickly, cover them with aluminum foil or a pie crust shield about halfway through baking.

Step 7: Cool Completely

This is the hardest part—waiting! Remove the pie from the oven and let it cool on a wire rack for at least 4 hours, preferably overnight. The filling needs this time to set up properly. If you cut into it too soon, the filling will be runny. I know it’s torture to wait when your kitchen smells amazing, but patience creates perfect slices. Once cooled, the pie can be served at room temperature or slightly warmed.