In a large bowl, whisk together 2.5 cups all-purpose flour, 1/2 tsp kosher salt, and 1 tsp granulated sugar. Add 1 cup cold cubed unsalted butter. Using a pastry cutter or your fingertips, cut the butter into the flour until mixture resembles coarse peas with some larger butter bits remaining (about 6–8 pulses if using a food processor).

Add ice water

Sprinkle 6 tablespoons ice water over the flour-butter mixture, a tablespoon at a time, tossing gently after each addition until dough just comes together when pressed (do not overwork). You should have enough moisture to hold the dough but still see flecks of butter.

Form and chill

Divide dough into two equal portions. Flatten each into a disk about 1-inch thick, wrap tightly in plastic wrap and refrigerate at least 1 hour (or up to 2 days) before rolling.

Apple Filling

Prep the apples

While dough chills (or up to 30 minutes before baking), peel, core and slice 6 apples into 1/4-inch slices. Toss slices in a large bowl with 1 tablespoon fresh lemon juice to prevent browning.

Combine dry filling ingredients

In a small bowl, mix 3 tbs granulated sugar, 2 tbs packed light brown sugar, 2 tbs all-purpose flour, 1.5 tsp ground cinnamon, 1/4 tsp ground nutmeg and 1/4 tsp salt until evenly blended.

Coat apples

Pour the dry sugar-spice mixture over the sliced apples and toss gently until all slices are evenly coated.

Assembly & Baking

Preheat oven and roll dough

Preheat oven to 425°F (220°C). On a lightly floured surface, roll one dough disk into a 12-inch circle for the bottom crust. Transfer to a 9-inch deep-dish pie pan, easing dough into the pan without stretching. Trim any excess leaving about 1/2-inch overhang.

Fill the crust

Mound the apple filling into the prepared bottom crust, making a slight domed pile. Dot the top of the apples evenly with 2 tablespoons unsalted butter cut into small pieces.

Top crust or lattice

Roll the second dough disk into a 12-inch circle. For a full top crust: place over apples, trim overhang to 1/2 inch and crimp edges to seal. Cut 4–6 vents in the center to allow steam to escape. For a lattice: cut the top dough into 10–12 strips and weave over the filling, trimming and crimping edges to seal.

Egg wash and sugar

Beat 1 large egg with 1 tsp cold water and brush evenly over the top crust. Sprinkle 1 tablespoon coarse sugar over the crust if desired for sparkle and crunch.

Bake

Place pie on a rimmed baking sheet to catch drips. Bake at 425°F (220°C) for 15 minutes, then reduce oven temperature to 375°F (190°C) and continue baking for 35–45 minutes more, until crust is golden brown and filling is bubbling. If crust browns too quickly, tent loosely with foil during the last 15 minutes.

Cool

Remove pie from oven and transfer to a wire rack. Let cool at least 2 hours so filling sets and slices cleanly.

Serve a la mode

Slice pie and serve each warm slice with 1 scoop (or more) of vanilla ice cream. The contrast of warm apple pie and cold ice cream is classic 'a la mode.'