Ingredients
To start, make your pie dough by combining the flour, salt, and sugar in a large bowl. Add your oil and mix just until the flour is slightly moist and clumpy. Add your butter, smashing the pieces with your fingers until it is mostly all incorporated, and the largest pieces are the size of a pea.
Add your cold water, tossing with a fork to evenly hydrate. Switch to your hands, pressing the pieces together. Once the dough comes together, transfer it to a floured surface and knead a few times. Cut into two even balls and wrap tightly in plastic. To make rolling your dough easier later, press the dough into a round while you wrap it. Refrigerate 1-2 hours.
To make the filling, combine your apple slices, sugars, lemon juice, salt, and spices. Mix and let sit at room temperature until juices have accumulated in the bottom, around an hour.
After around 30 minutes, add your apple cider and vanilla bean paste to a pot over medium heat. Bring to a boil and boil until reduced by ½ - ⅔. Carefully pour the juices from your bowl into the reduced cider, and continue to boil until you have roughly ½ cup of liquid. In the meantime, combine your cornstarch with 3 tbsp cold water and mix to create a slurry.
When you have around ½ cup of liquid left, add your cornstarch slurry, whisking constantly until thick and bubbly, 1 minute. Remove from heat and pour over apples, tossing to combine.
Get one of your dough balls from the fridge and roll it out into roughly a 12inch circle. Having an exact circle doesn't matter, as you can always patch up any holes with scraps. Roll your dough over your rolling pin, and carefully transfer the dough to your pie plate. Slump the dough into the plate, making sure you don't pull or tug at the dough. Gently, but firmly, press the dough into all the sides, walls, and bottom of the plate.
Beat your egg in a small bowl with some water, and then gently brush the egg wash over the base of the dough. Pile your apples into the pie dish, leaving a mound in the center, and place the pie in the fridge to cool while you cut the top strips.
Remove your second dough ball from the fridge and roll it out into a roughly 12 inch square. Using a pizza cutter, cut 1 inch strips and set aside. Grab your pie from the fridge and create a lattice pattern, overlapping strips as you go. If you don’t want to do a lattice, you can also leave the top crust a full sheet, and punch out some holes to allow air to escape.
Gently egg wash the top crust and sprinkle demerara sugar all over. Place the pie in the freezer while you preheat your oven to help lock in your design.
Preheat the oven to 375F and line a baking sheet with tinfoil. This will catch any drippings and prevent your oven from smoking.
Transfer the pie to the foil lined baking sheet and bake for 1 ½ - 2 hours, until the top is deeply golden, and the juices bubble. Let cool for 3-4 hours before slicing. Once cool, keep covered at room temperature until ready to serve.
