Pie Dough (you will have some leftover). Prepare ahead of time.
2 tablespoons unsalted butter
3 pounds Golden Delicious, Honeycrisp, or Pink Lady apples, peeled and cored, then cut into thick slices
1/4 teaspoon ground allspice
1/2 teaspoon ground cinnamon
1/4 teaspoon kosher salt
1/3 cup (heaping) sugar
2 tablespoons all-purpose flour
2 teaspoons cornstarch
Juice of 1 lemon
1 egg, lightly beaten with 2 T milk
Make the pie dough first, giving it at least an hour to sit in the refrigerator.
Melt butter in a large sauté pan set over medium-high heat and add apples to the pan. Stir to coat fruit with butter and cook, stirring occasionally. Meanwhile, whisk together the spices, salt and sugar, and sprinkle this over the apples, stirring gently to combine. Lower heat and cook until apples have started to soften, approximately 5 to 7 minutes. Sprinkle the flour and cornstarch over the apples and continue to cook, stirring occasionally, another 3 to 5 minutes. Remove pan from heat, add lemon juice and stir to combine. Scrape apples into a bowl and allow to cool completely.
Place a large baking sheet on the middle rack of oven and preheat to 425. Remove pie dough from the refrigerator and knead briefly on a floured surface to soften (be very brief - you want it to just come together). Use a rolling pin to roll it out (use flour sparingly, but as necessary) until it is roughly 12 inches in diameter. Fit this crust into a 9-inch pie plate, trimming it to leave a 1/2-inch overhang. Place this plate, with the dough, in the freezer.
Roll out the remaining dough on a lightly floured surface until it is roughly 10 or 11 inches in diameter.
Remove pie crust from freezer and put the cooled pie filling into it. Cover with remaining dough. Press the edges together, trim the excess, then crimp the edges with the tines of a fork. Using a sharp knife, cut three or four steam vents in the top of the crust. Lightly brush the top of the pie with egg wash (the egg/milk mixture) and sprinkle with a teaspoon or so of sugar.
Place pie in oven and bake on hot baking sheet for 20 minutes, then reduce temperature to 375. Continue to cook until the interior is bubbling and the crust is golden brown, about 30 to 40 minutes more. Remove and allow to cool on a windowsill or kitchen rack, about two hours.