Mix together flour, salt and sugar. Add the unsalted butter, cut into small pieces, and combine until mixture looks like coarse meal. Begin adding the ice water slowly with the mixer running, until the dough begins to hold together.
Turn out onto a floured surface and divide into two pieces. Wrap each piece in plastic wrap, and refrigerate for 30 min to an hour before using. (This will make the dough easier to work with and help the pastry to bake better).
Take your dough out of the refrigerator, and roll the first piece into a circle that’s about 13-in in diameter (to fit a 9-in pan dish). This will be the bottom layer of the pie, transfer it into your greased dish, and press into sides. Prick the bottom with a fork a couple times so that it doesn’t rise as it bakes.
Peel and chop your apples, and in a large bowl toss them with the lemon juice, flour, sugar, cinnamon and nutmeg and salt.
Arrange your apples into the crust, and roll out the second piece of dough, just like the first. Place on top of the apples, you should have a border of dough hangs over the dish, tuck the dough under, and crimp the edges with a fork. This will seal the sides and make sure that no liquids escape.
Chill the pie in the fridge for another 15 minutes (this will make it firmer, and will make it easier for you to brush the pie with the egg wash. However, if you’re in a hurry, you can skip this step!)
Remove the pie from the fridge, and make an egg wash by combining an egg yolk with a tbs of cold water. Brush the pie with the egg wash, and cut four vents at the top of the pie, so that steam can escape while your pie bakes.
Preheat your oven to 425 deg F and bake for about 25 minutes, until the crust begins to look golden brown, then lower the oven temperature to 350 deg F and bake for another 25 to 30 minutes until it is golden brown and the juices are bubbling. Let stand for 30 minutes before serving. All you need is some vanilla ice cream, or any other ice cream you like to serve with your warm apple pie!
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