Combine Dry Ingredients: In a large mixing bowl, mix the flour, sugar, and salt.
Cut in the Butter: Using a pastry cutter or food processor, cut the chilled butter into the flour mixture until it resembles coarse crumbs.
Add Ice Water: Gradually add ice water, one tablespoon at a time, mixing until the dough just comes together.
Chill the Dough: Divide the dough into two discs, wrap them in plastic wrap, and refrigerate for at least 30 minutes.
Mix Strawberries: In a large bowl, combine the strawberries, sugar, cornstarch, lemon juice, and vanilla extract. Toss until the strawberries are evenly coated.
Roll Out the Dough: On a floured surface, roll out one disc of dough into a 12-inch circle. Transfer it to the pie pan.
Add Filling: Pour the strawberry filling into the crust, spreading it out evenly.
Top Crust: Roll out the second disc of dough and place it over the filling. Trim any excess dough and crimp the edges to seal.
Egg Wash: Brush the top crust with the beaten egg mixed with water. Cut a few slits in the top to allow steam to escape.
Preheat the Oven: Preheat your oven to 425°F (220°C).
Bake: Place the pie in the oven and bake for 20 minutes. Reduce the heat to 375°F (190°C) and continue baking for another 30 minutes or until the crust is golden brown and the filling is bubbling.
Cool: Allow the pie to cool on a cooling rack for at least 2 hours before serving to let the filling set.