In a food processor, add All-Purpose Flour (2 cup) and Butter (3/4 cup) plus 1 tablespoon. Process until mixture looks like fine breadcrumbs.
Add Egg (1) yolk and Water (3 tablespoon). Process again until mixture comes together as dough.
Lightly knead the dough on a floured surface until smooth. Form into a rough disk shape, cover with plastic wrap and chill in fridge for 1 hour.
Once chilled, cut the dough in half. Roll it out on a lightly floured surface. Drape the pastry over a pie plate and trim off any excess.
Let crusts chill in the fridge for 10-15 minutes.
Place baking paper in each pie plate and hold down with pie weights to keep the pastry from rising.
Bake at 200 degrees C (400 degrees F) for 10 minutes.
Remove pie weights and baking paper, then bake for another 10 minutes, or until golden.
In a mixing bowl, add Sweet Potato (1 kilogram) and 1 tablespoon of chopped butter. Mash until there are no big lumps. Let cool.
Transfer sweet potato mixture to blender. Add Orange Juice (1/3 cup), Brown Sugar (1 cup), Ground Cinnamon (2 teaspoon), Vanilla Extract (1 teaspoon) and the 3 whole Egg (3). Blitz until smooth.
Divide the sweet potato mixture between the two pie plates.
Reduce the oven temperature to 350 degrees C (180 degrees F) and bake for 10 minutes, or until filling is set.
Drizzle Dark Chocolate (to taste) over the pie. Serve and enjoy!