In a large mixing bowl, combine 2 ½ cups of all-purpose flour, 1 tablespoon of granulated sugar, and 1 teaspoon of salt. Cut in 1 cup of chilled, cubed unsalted butter until the mixture resembles coarse crumbs. Gradually add 6-8 tablespoons of ice water, mixing until the dough holds together. Divide into two discs, wrap in plastic wrap, and refrigerate for at least 1 hour.

Preheat the oven to 375°F (190°C) while your dough chills. Prepare your baking sheet by lining it with parchment paper.

In a bowl, combine 4 cups of hulled and halved fresh strawberries, ¾ cup of granulated sugar, 2 tablespoons of corn starch, the juice of 1 lemon, and 1 teaspoon of vanilla extract. Toss gently until the strawberries are coated.

Roll out one chilled dough disc on a floured surface until about 12 inches in diameter. Transfer to a 9-inch pie pan, gently pressing it into the bottom and up the sides.

Pour the strawberry mixture into the prepared crust, spreading it evenly. Dot the filling with small pieces of 1 tablespoon of unsalted butter.

Roll out the second chilled dough disc and place it over the filling, crimping the edges to seal. Cut slits into the top crust for venting.

Whisk together 1 beaten egg and brush it over the top crust. If desired, sprinkle 1 tablespoon of turbinado sugar over the crust.

Bake in the preheated oven for 45-55 minutes until golden brown and bubbly. The filling should be bubbling through the crust slits.

Allow the pie to cool for at least 30 minutes before serving.