(Adapted from The Joy of Cooking, by Irma S. Rombauer, Marion Rombauer Becker, and Ethan Becker, originally published in 1931)
Cut 6 tablespoons of butter into a cup of flour, then add grated lemon peel (to taste), 1 heaping tablespoon of sugar, a dash of salt, and 1 egg yolk (put aside egg white). Mix together and add cold water, frisking it in with a fork, until the dough just sticks together. Put it in a plastic bag and refrigerate so it gets all cold.
Peel and slice apples into a bowl. Add the juice of 3 lemons, 1 grated lemon peel, and a ½ cup of brown sugar. Let sit for 1 hour. Pour off the majority of the liquid into a separate bowl, and add a 1 tablespoon of cornstarch to the apple mixture.
1) Roll out the dough on a floured board, slide it into a pie pan, and brush the whole thing with the raw egg whites.
2) Put it into a pre-heated 450° oven for about 10 minutes, or less—just to harden the egg white and make a non-porous surface for all the juicy apples, but don't brown the crust too much!
3) Turn the oven down to 300° or 350° and let crust cool a bit. Lay the apple mixture in the pie crust in a pleasing way (!) and top with tiny pats of butter here and there and about 2 tbsp of brown sugar.
4) Bake until the apples are a bit soft and the crust is browned but not burned—I cover it with aluminum foil at a certain point because the crust starts to burn before the apples are soft.
5) Meanwhile, put the reserved apple mixture liquid into a small saucepan. Add 1 and a ½ (or so) tablespoons cornstarch and stir slowly over a low flame until the sauce starts to thicken, then pour it over the pie. If it gets too thick, just add a little bit of water or lemon juice. Be careful when adding the cornstarch to the liquid mixture—if you add too quickly without stirring the liquid will clump up into balls.
6) Serve and enjoy!