Pour the apple cider into a large pot or Dutch oven and bring it to a boil over medium-high heat. Cook until it’s reduced by about half, about 3 minutes, then reduce the heat to medium and add the butter.
When the butter has melted, add the brown sugar and lemon juice and cook, stirring constantly, until the sugar has melted and the mixture is mostly smooth, about 2 minutes.
Add the apples and stir to coat them in the sugar mixture. Cook, stirring occasionally, until the apples begin to cook down and release their liquid, about 5 minutes.
Add the cinnamon, ginger, cardamom, and salt, then grate in the nutmeg, if you’re using fresh! (If not, just add the ground nutmeg with the rest of the spices.) Cook, stirring, for about 2 minutes, to incorporate the spices and cook the apples down a bit more.
In a small bowl, whisk together ½ cup of the granulated sugar, ¼ cup of the flour, and the cornstarch.
Sprinkle the mixture evenly over the apples then cook, stirring, until bubbling and very thick, 3 to 4 minutes. (The cornstarch needs to bubble in order to thicken, so be sure to get it to that stage!) Remove from the heat and stir in the vanilla.
To stop the cooking process, pour the apples onto a sheet pan and spread them out to cool to room temperature, about 30 minutes.
Place one of the rolled-out crusts into a 9-inch pie pan, draping the excess over the edge. Sprinkle the remaining ¾ teaspoon granulated sugar and ¾ teaspoon flour over the bottom of the crust. This will help soak up the excess juices in the pie and keep the crust from getting soggy!
Scrape the apples into the crust and even them out, leaving them a little higher in the center.
Roll the second crust on a rolling pin to easily transfer it to the top of the pie, then unroll it over the apples.
Trim off the excess of both crusts so that there’s only about ¼ inch of overhang. Working around the pie, tuck the edge of the top crust under the edge of the bottom crust.
Once the edge is tucked and neat, crimp the edge however you like, using the tines of a fork or pinching with one hand while pressing with a knuckle on your other hand. At this point, if you have time, you can refrigerate the pie for 1 hour before baking, to help it bake more evenly.
When you’re ready to bake the pie, preheat the oven to 400°F with a rack set at the lowest level. Cut four slits in the pie’s top crust, brush the top with egg wash, and sprinkle the whole surface with the turbinado sugar.
Set the pie on a sheet pan and bake until the crust begins to turn golden, about 30 minutes. Reduce the temperature to 350°F and rotate the pie. Bake until the pie is deep golden and the filling is bubbling through the vents, about 1 hour 10 minutes. If the pie seems to be getting brown too quickly, cover it loosely with foil for the rest of the baking process.
Let the pie cool to almost room temperature before slicing (the apples will hold together better that way!) Serve it with vanilla ice cream on the side, or a big dollop of whipped cream on top!
