Prepare the pie crust: In a large bowl, whisk together 375g (3 cups) of all-purpose flour, 1 tsp (5g) of salt, and 2 tbsp (25g) of granulated sugar. This dry mixture forms the base of your flaky crust.

Add the cold, cubed 225g (1 cup) of unsalted butter to the flour mixture. Use a pastry blender, two forks, or your fingertips to cut the butter into the flour until the mixture resembles coarse crumbs with some pea-sized pieces of butter remaining. These butter pieces are crucial for creating flaky layers. Tip: If using your fingers, work quickly to prevent the butter from melting.

Gradually add 120-180ml (1/2 cup to 3/4 cup) of ice water, one tablespoon at a time, mixing gently after each addition until the dough just comes together. Be careful not to overmix, as this can result in a tough crust. The dough should be moist enough to hold together when squeezed, but not sticky.

Divide the dough in half, shape each half into a flat disk, wrap tightly in plastic wrap, and refrigerate for at least 1 hour (or up to 2 days). This chilling period allows the gluten to relax and the fat to firm up, making the dough easier to roll and contributing to flakiness.

Prepare the apple filling: In a large bowl, combine the peeled, cored, and sliced 1.5kg (about 6-7 medium) apples. Add 150g (3/4 cup) of granulated sugar, 50g (1/4 cup) of packed brown sugar, 60g (1/2 cup) of all-purpose flour, 2 tsp (5g) of ground cinnamon, and 1/4 tsp (1g) of ground nutmeg. Toss gently to coat the apple slices evenly.

Add 1 tbsp (15ml) of lemon juice to the apple mixture. The lemon juice brightens the apple flavor and helps prevent browning. Toss again to ensure the lemon juice is distributed. Set aside.

Preheat your oven to 200°C (400°F). Have a baking sheet ready to place the pie on, which will catch any drips.

On a lightly floured surface, roll out one disk of chilled pie dough into a circle approximately 30cm (12 inches) in diameter and about 0.3cm (1/8 inch) thick. Carefully transfer this dough to a 23cm (9-inch) pie plate. Gently press the dough into the bottom and up the sides of the plate. Trim any excess dough, leaving about a 1.5cm (1/2 inch) overhang.

Pour the prepared apple filling into the pie crust-lined plate. Dot the top of the filling with the 30g (2 tbsp) of small pieces of unsalted butter. These will melt and add richness to the filling.

Roll out the second disk of dough. You can either place it as a solid top crust, cutting vents for steam to escape, or cut it into strips for a lattice top. If making a solid top crust, place it over the filling. Trim the excess dough, leaving about a 1.5cm (1/2 inch) overhang. Crimp the edges of the top and bottom crusts together to seal. Cut several slits in the top crust with a sharp knife to allow steam to escape during baking. If making a lattice, cut the dough into strips and weave them over the filling.

Brush the top crust (or lattice) with the beaten egg wash. This will give the pie a beautiful golden-brown sheen. Sprinkle the top evenly with 1 tbsp (12g) of granulated sugar for a slight crunch and sparkle.

Place the pie on the preheated baking sheet. Bake at 200°C (400°F) for 20 minutes. This initial high heat helps to set the crust.

Reduce the oven temperature to 190°C (375°F) and continue baking for another 30-40 minutes, or until the crust is golden brown and the filling is bubbling. If the crust starts to brown too quickly, you can loosely tent the pie with aluminum foil.

Once baked, carefully remove the pie from the oven and let it cool on a wire rack for at least 2-3 hours before slicing and serving. This cooling period is essential for the filling to set properly, preventing a runny pie. Serving warm is traditional and delicious.