Crust

2 1/2 cups all-purpose flour, plus more for rolling
1 teaspoon salt
2 sticks unsalted butter, cut into 1/2-inch dice and chilled
1/4 cup ice water

Filling

3 pounds apples, such as Pink Lady, Golden Delicious, Cortland or Jonathan—peeled, cored and sliced 1/4 inch thick
1 cup sugar
1/3 cup all-purpose flour
1/2 teaspoon cinnamon
1/4 teaspoon freshly grated nutmeg
Pinch of salt
2 tablespoons fresh lemon juice
2 tablespoons unsalted butter, cut into small dice
1 large egg, beaten
2 tablespoons turbinado sugar, for sprinkling