Step 1In a medium bowl, sift together the flour and salt. Place the flour and salt mixture in a large sealable plastic bag. Add the butter cubes to the bag and toss to distribute. Squeeze out the excess air before sealing.
Step 2Use a rolling pin and roll over the bag, flattening the butter into flakes. Chill the flattened mixture for 30 minutes, then sprinkle one-fourth cup water over the butter/flour mixture. Quickly stir until the mixture forms a dough that holds together when pinched. If the mixture is too dry, continue to add water, 1 tablespoon at a time, until the dough comes together. Be careful not to overwork the dough or it will become tough.
Step 3Form the dough into 2 flat disks 5 to 6 inches in diameter. Wrap the disks tightly in plastic wrap and chill again.
Step 4On a floured board, roll out each crust with a rolling pin to a diameter of about 12 inches (for a 9-inch pie). If the fruit is piled high in the bottom crust, you may need to roll the top crust a little larger than 12 inches; just make sure you have enough dough to go over the mounded fruit with a half-inch overlap.
Step 1Heat the oven to 450 degrees.
Step 2Starting around the outside edge, line the pie crust with apple chunks. Move in concentric circles inward. When you've got the bottom layer covered, mound the rest on top. Go for density without overcrowding.
Step 3In a medium bowl, mix together the granulated sugar, cinnamon, nutmeg, cayenne, salt and lemon zest. Sprinkle the sugar/spice mixture evenly over the top of the apples, then sprinkle over the brown sugar. (Don't worry, it'll all migrate downward.) Cut the butter into tiny chunks and scatter it around, randomly but evenly over the top of the sugar.
Step 4Put the top crust on, crimp, then cut steam holes and brush on the egg wash. Chill the pie for 20 minutes or so before baking.
Step 5Place the pie in the oven and bake for 15 minutes. Reduce the heat to 350 and bake until the juices are bubbling but the fruit still feels firm (use a toothpick or the tip of a paring knife to reach through a vent hole to pierce a piece of apple), another 30 to 40 minutes. Remove the pie to a cooling rack.
Step 6Cool the pie to room temperature before serving. A few hours is fine, even overnight is good. The flavors will blend and mellow, and the juices will have time to solidify.