Ingredients:

5 pounds mixed apples, such as granny smith, gala and mcintosh (about 12 apples) (filling)

1 cup granulated sugar (filling)

3 tablespoons lemon juice (filling)

1/4 teaspoon kosher salt (filling)

1 stick (8 tablespoons) unsalted butter (filling)

3 tablespoons all-purpose flour (filling)

1 teaspoon ground cinnamon (filling)

4 sticks (1 pound) unsalted butter, at room temperature, plus more for greasing (dough)

1 1/4 cups confectioners' sugar (dough)

1 teaspoon kosher salt (dough)

5 cups all-purpose flour (dough)

1 large egg, plus 1 large egg separated (dough)

turbinado sugar, for sprinkling (dough)

Directions:

1. Special equipment: one 10-by-15-inch rimmed baking sheet, 1 pastry bag and one 1/4-inch round pastry tip (no. 803) and an extra-large skillet

2. For the filling: Peel and core the apples; cut into 1/4-inch-thick slices. Toss with the granulated sugar, lemon juice and salt in a large bowl. Melt 6 tablespoons of the butter in an extra-large skillet over medium-high heat. Add the apples, and cook, stirring frequently, until the firmer apples soften but hold their shape, about 12 minutes. Add the flour and cinnamon, and stir to combine. Remove from the heat, and let cool completely. (The filling can be made up to 2 days ahead; cover and refrigerate.)

3. Position an oven rack in the top of the oven, and preheat to 350 degrees F. Butter the bottom and sides of a 10-by-15-inch rimmed baking sheet; set aside.

4. For the dough: Combine the butter, confectioners' sugar and salt in a large bowl, and beat with an electric mixer until smooth, about 1 minute. Add half the flour, and beat to incorporate; add the remaining flour, and beat until the dough just starts to come together in large, soft clumps (it should hold together when squeezed). Set aside 2 lightly packed cups of the dough for the lattice top.

5. Scatter the remaining dough in the prepared baking sheet. Press some into and up the sides of the baking sheet until it forms a ridge 1/4 to 1/2 inch above the rim and is about 1/4 inch thick. Press the remaining dough into the bottom of the sheet until it is 1/4-inch-thick and the sheet is completely covered, with no gaps. (Don't worry about overworking the dough slightly.) Use your fingers to decoratively crimp the ridge of dough around the edges. Bake until lightly golden, 20 to 25 minutes. Let cool completely on a rack.

6. To assemble: Pack the cooled filling into the cooled pie shell, making sure the surface is flat. Dot with the remaining 2 tablespoons of butter.

7. Put the reserved 2 cups of dough in a large bowl. Add the egg and egg white, and beat until incorporated. Transfer the dough to a pastry bag fitted with a 1/4-inch round pastry tip (no. 803). 8. To pipe a lattice on top of the filling, start in one corner of the pie, steadily squeeze the bag and drag the dough across the filling in diagonal lines about 1 1/2 inches apart. Turn the pie a quarter turn, and continue piping lines across to form a crosshatch or lattice design.

9. Bake the pie for 20 minutes. Remove and brush the crust (edges and lattice) with the egg yolk whisked with a splash of water. Sprinkle generously with turbinado sugar, and bake until the crust is golden brown and the filling bubbles slightly, 20 to 25 minutes. Serve slightly warm or at room temperature. (The pie can be baked, cooled, covered and refrigerated up to 2 days ahead.)

Bon Appetit!