To prepare the crust:

1. Whiz the flour, sugar, and salt in a food processor to combine (Note: you can also do this by hand with a pastry cutter!) Pulse in the shortening and butter, just until evenly dispersed in pea-sized clumps. Begin adding ice water 2 tablespoons at a time until moist clumps begin to form. Remove dough from food processor, form it into a flat round disk, and wrap in plastic wrap. Chill in the fridge for at least an hour prior to use.
2. When you’re ready to bake the pie, roll the dough out on a well-floured surface into a 1/8-1/4” circle about an inch larger than your pie plate on all sides. Roll the dough loosely back onto the rolling pin and lift it into the pie dish. Gently fit the dough into the pie plate and trim off any excess dough leaving a 1” border around the edge of the dish. Fold the lip of the dough under so that it extends just over the edge of the pie plate and crimp the edges as you prefer. Prick a few holes in the bottom of the dough with a fork and place the whole pan into the freezer to chill briefly, about 15 minutes. In the meantime, preheat the oven to 350 degrees.
3. When the oven is preheated, remove the pie plate from the freezer and line the insides of it with a piece of parchment paper. Use either pie weights or dry beans/rice to weigh down the dough and bake for about 20 minutes. After this initial bake, remove the pie weights, brush the entire crust with a thin layer of egg wash (the egg whisked with water), and bake for an additional 5-10 minutes or until golden brown. Set aside to cool while you prepare your filling.

To prepare the filling:

1. In a heavy-bottomed pan, whisk together the sugar, cocoa powder, flour, and salt. Slowly add in the milk, stirring all the while, and set the pan over medium-low heat. Keep stirring regularly until the mixture comes to a bubble. Continue stirring and cooking an additional 1-2 minutes, removing from heat only once the mixture has thickened to a mayonnaise consistency. Carefully scoop up a cup of the hot mixture in a measuring cup of ladle and slowly add it to the eggs, whisking them all the while to ensure they don’t scramble under the heat of the pudding. Once the entire cup has been added, pour the egg mixture back with the remaining pudding in the pan, stir, and place back on low heat. Bring to a bubble again and cook for an additional minute and a half to thicken and then remove from heat. Stir in the vanilla and butter and pour the mixture into the prepared pie crust. If you find the pudding has clumps, you can use a fine-mesh strainer to strain out any while you pour it into the crust. Place a sheet of plastic wrap directly on top of the filling and refrigerate until cooled and firm.
2. Once cooled, prepare your topping by beating the whipping cream in a large bowl on medium speed until thickened to soft peaks. Slowly add in the sugar and continue whipping until thickened to a cloud-like consistency. Serve immediately!