In a large bowl combine flour, sugar, and salt. Cube butter into small cubes. With a pastry blender, blend butter and flour until crumbles form. Slowly add in your ice water a little add a time, incorporating with your pastry blender after each pour. The dough can vary consistency because of climate (if you live in a dry climate you may need a little more water or less in a moist climate). Form into two disk shapes, wrap in plastic wrap and refrigerate for at least two hours.
Bring the dough to room temp and roll the out on a well-floured surface. The dough may seem tough to roll out but apply pressure. Roll your 9-inch dough around your rolling pin and roll over your pie dish. Set into the fridge until the filling is ready.
Preheat oven to 350 degrees
Cut and peel apple into slices and mix with sugar, cinnamon, juice, zest, nutmeg, allspice, salt, and flour. Allow apples to macerate for 10-15 minutes to release their juice. Pour into uncooked pie shell. Roll out your other dough disk and design the top of the pie with crust design of your choice.
Whisk egg and milk mixture and brush with a pastry brush over pie crust.
Bake at a 350 degree Fahrenheit oven for 50-60 minutes until the fruit is bubbling and your crust is golden brown.