Start by making your favorite double pie crust recipe. Divide the dough in half, wrap each half in plastic wrap, and chill in the fridge as directed, forming two disks. This chilling step is important for achieving a flaky crust.
While the dough chills, prepare the filling. In a saucepan, combine 1 cup of the fresh blueberries with the sugar. Turn on the heat and bring it to a gentle simmer, stirring occasionally. You’ll know it’s ready when the sugar has completely dissolved, which should take about 5 minutes.
In a small bowl, combine the cornstarch and water, whisking until smooth. This mixture will help thicken the blueberry filling. Once the sugar is dissolved, whisk this mixture into the blueberry mixture, stirring constantly.
Return the saucepan to the heat and cook, stirring continuously. You want to keep it over low heat until it begins to boil, thickens, and turns clear. The bubbling filling is a sign that it’s ready!
Once thickened, transfer the filling into a large bowl. Mix in the lemon zest, cinnamon, nutmeg, and butter. Stir gently, then fold in the remaining blueberries. Let the mixture cool while you prep the crust.
Preheat your oven to 400ºF (200ºC). Roll out one of the chilled pie crust disks and fit it carefully into the bottom of your pie plate. Trim any excess dough around the edges.
Now, it’s time to add that beautiful blueberry filling. Spoon it into the crust, spreading it evenly. You want to ensure every slice gets a taste of that sweet filling.
For the lattice topping, roll out the second crust. Cut it into strips around 1 inch wide. You can get creative here! Weave the strips over the filling to create a lattice pattern, or simply lay half in one direction and top with the others diagonally.
Seal the edges of the pie by crimping them with your fingers or a fork. For a finishing touch, sprinkle a little sugar on top of the lattice. It adds a lovely sweetness and will caramelize beautifully in the oven.
Place the pie on a parchment-lined baking sheet to catch any drips. Put it on the lower shelf of your oven. Immediately lower the oven temperature to 375ºF (190ºC) and bake for about 40 minutes. You want the crust to be golden brown and the filling to be bubbling.
Once baked, let the pie cool on a wire rack. This will allow the filling to set properly, making it easier to slice and serve.