For Peach Pie Filling

6 c. sliced peaches
1½ T. lemon juice
1¼ c. sugar
⅓ c. flour
1 tsp. cinnamon
¼ tsp. nutmeg
Egg wash (1 large egg whisked with 1 teaspoon water and a pinch of salt)
Demerara sugar, for finishing

For All Butter Pie Crust:

2½ cups unbleached all-purpose flour (312g)
1 teaspoon kosher salt
1 tablespoon granulated sugar
½ pounds (2 sticks) cold unsalted butter, cut into ½-inch pieces
1 cup cold water
¼ cup cider vinegar
1 cup ice