In a medium sized bowl, combine flour, sugar, and salt. Stick the bowl and a pastry cutter*/fork in the freezer.

Cut the butter and shortening into chunks. Take the bowl from the freezer and add the butter and shortening. Using a pastry cutter or fork, cut the butter into the flour mixture until the mixture resembles a coarse meal. The biggest chunks of fat should be pea sized and all fat chunks should be coated in flour. Alternatively you can pulse in a food processor to get the same result.

Place the bowl in the freezer again. Prepare the ice water.
 Remove the bowl from the freezer. Keep adding ice water 1 tablespoon* at a time, gently tossing the mixture with a fork. Fully combine the water before adding more. When squeezing a small amount of dough in your fist forms a ball, it's ready. If the dough still crumbles and doesn't stick together, continue adding water one tablespoon at a time.

Gently knead the dough together in the bowl so it forms a cohesive ball. Split the dough in two pieces, with one piece about 60% of the dough and the other about 40%. Gently flatten each ball into a disc about 1 1/2" tall.
 Wrap both discs in plastic wrap. Place in the fridge to rest for 2 hours.

Remove the larger disc. Lightly flour a work surface. Roll out the disc, flouring over and under the dough as you go to prevent sticking. Roll the dough to 14.5" in diameter. 
Fold the dough in half, and then in half again. Gently place it in the pie pan and unfold. Ease the dough into the pan rather than stretching it to get it in the edges. Then gently press the dough to the sides of the pan. Trim the edge of the dough so that it overhangs the pan by 1/2". 
Add the scraps to your other dough disc. Place pie pan in the fridge.

Combine the apples, granulated sugar, brown sugar, cinnamon, nutmeg, lemon zest, and lemon juice. Let sit for 30 minutes.

Preheat oven to 400F.

Strain the apples from the juices. Add the juices to a small sauce pan on medium heat and bring to a simmer for 4 minutes. Remove from heat and stir in butter until melted. Mix the reduced juices with the apples. Toss in the flour and cornstarch.

Pour the filling into your prepared pie dish. Use the bottom of a serving spoon or spatula to gently press the apples together. Place in fridge.

Roll out your other disc of dough on a light floured surface to 10” in diameter. Lay it on top of the apples. Trim the edges so there is just a 1/2” overhang.

Fold the dough (you should have two layers now) underneath itself to create a thick edge. Create scallops by pinching with your fingers, or crimp the edges using a fork.

Combine the egg and heavy cream and brush over the crust. Cut a few slits in the top for ventilation.

Bake for 20 minutes, then reduce oven temperature to 375°F and bake for an additional 35 to 40, or until filling has been bubbling for at least 5 minutes. If pie is browning too quickly, lay a piece of aluminum foil over top.

Let sit on a wiring cooling rack for 3 hours before serving.