Prepare homemade pie crust according to recipe (or use store bought). Roll out bottom crust between two pieces of parchment paper first (dust the dough with flour liberally before rolling), place in a 9 inch deep dish pie plate, prick bottom with a fork and place in freezer until pie filling is ready. Roll out top crust and place on a cookie sheet that will fit in your freezer. Place in freezer until ready to use. Turn on oven to 350 degrees and position rack in lower third of oven.
Peel, core, and slice apples into 1/4″ slices. Sprinkle with lemon juice and mix well. Put into a large pot.
In a medium bowl, mix white sugar, brown sugar, salt, corn starch, and ground cinnamon. Add to the apples in the large pot over medium heat. Add butter pieces. Mix thoroughly and heat apples until slightly soft, approximately 7-10 minutes.
Pour apple mixture into pie crust. It will be overflowing! Pack the apples down as much as possible to remove the majority of space between the apples. Top with top pie crust and crimp edges to seal. Slice the top crust two or three times to allow to vent. Brush with milk, then sprinkle with coarse sugar and nutmeg.
Place in oven for 30 minutes, then tent cover with aluminum foil (spraying the underneath side of foil with oil first to prevent sticking). Bake another 20-30 minutes until the crust is a nice golden-brown and the filling is bubbling. Let cool on a rack for 2-4 hours to let sit. Serve with ice cream and enjoy!