Ingredients

3 1/4 cups unbleached all-purpose flour, plus more for dusting 

1 tablespoon sugar 

2 1/2 teaspoons kosher salt (we use Diamond Crystal) 

2 1/2 sticks cold unsalted butter, cut into small pieces 

1/2 cup ice-cold water, plus more as needed 

2 3/4 pounds ripe peaches (8 to 10 medium) 

3/4 cup sugar 

1/2 vanilla bean, split and seeds scraped 

1 tablespoon fresh lemon juice 

1/2 teaspoon kosher salt (we use Diamond Crystal) 

1/4 cup cornstarch 

Unbleached all-purpose flour, for dusting 

1 large egg, whisked

Preparation

For the Crust: In a large bowl, whisk together flour, sugar, and salt. Use your fingers to break up butter and cut it in, until mixture resembles mostly coarse meal with a bunch of hazelnut-size pieces remaining. Drizzle with ice water and stir with a fork until most of flour is moistened (mixture will still be shaggy and not at all formed into a dough). If there is dry flour remaining, add more ice water, 1 tablespoon at a time, until a piece will hold together when pressed between your fingers.

Turn dough out onto a clean surface and gather into a mound. Using the heel of your hand, smear dough away from you, working your way down to create long layers of butter. Fold dough over onto itself, as if closing a book. Repeat twice more. (There should be plenty of large, flat pieces of butter visible in dough.)

Divide dough into two pieces, one about 12 ounces, the other about 1 pound. Pat smaller piece into a round and larger into a rectangle. Wrap each loosely in plastic, then use a rolling pin to flatten and finish compacting (use plastic rather than your hands to maneuver dough—the less body heat transferred, the better). Refrigerate until firm, at least 1 hour and up to 1 day.

For the Pie Filling: Prepare an ice-water bath and bring a large pot of water to a boil. Cut an X in flower (non-stem) end of each peach. Drop in boiling water and cook just until skins begin to peel back, about 30 seconds. Transfer to ice-water bath, then peel and pit peaches. Cut into 1/2-inch wedges (you should have 7 to 8 cups).

In a large bowl, stir together sugar and vanilla seeds, then add peaches, lemon juice, and salt; stir to combine. Let stand 30 minutes, then stir in cornstarch. Set a colander over a heatproof bowl; transfer peaches to colander to drain. Transfer liquid in bowl to a small saucepan, then transfer peaches to bowl. Bring liquid to a boil over medium-high heat, then cook, whisking constantly, until thickened to the consistency of loose pudding, 1 to 2 minutes. Stir into peaches; let stand 15 minutes.

Assembly: On a lightly floured surface, roll out smaller piece of dough into a 13-inch round, about 1/8 inch thick. Fit into a 9-inch pie dish. Fill with peach mixture. Roll larger piece of dough out into an approximately 12-by-16-inch rectangle, a scant 1/8 inch thick. Using a pastry wheel or large knife, cut into 1 1/2-to-2-inch-wide strips.

Place 6 strips atop pie, leaving a little space between them. Fold back every other strip, and lay a strip across center of pie, perpendicular to original strips. Unfold folded strips, then fold back remaining strips. Lay another horizontal strip across pie. Repeat folding and unfolding strips to weave a lattice pattern. Repeat on remaining side. Press edges together to seal. Trim dough to a 1-inch overhang, fold under, and crimp as desired. Refrigerate 15 minutes.

Preheat oven to 400°F. Brush top of chilled pie with beaten egg. Place on middle rack of oven and slide a baking sheet or a piece of aluminum foil onto rack below to catch any overflow. Bake 15 minutes, then reduce temperature to 375°F and bake until bubbling in center and top and bottom crusts are browned, about 1 hour, 30 minutes more.

Let cool completely on a wire rack, at least 4 hours. Pie is best eaten the day it’s made, but can be stored, lightly covered, at room temperature, up to 2 days.