In a food processor place the flour, sugar and salt and process until combined. You can also do this by mixing with a fork or a dough blending tool.
Add in the butter and vegetable shortening and process until you get sand-like consistency (which you can also do using a fork, a dough blending tool or using the tips of your fingers).
After add in the cold water and the white vinegar and process (or combine with your hands) until a soft dough forms.
Wrap this dough in plastic kitchen wrap and let it rest in the refrigerator for 30 min.
Preheat the oven to 350°F and, once the dough has rested, take it out of the fridge and roll it out using a rolling pin on a clean and floured surface until it´s about 0.05 inches (5 mm) thick.
Place the rolled out dough on 4 small pie pans previously greased (we used 4" -10cm- diameter molds) in a way that covers them all, walls included, making some decorations to make the edges pretty if you want to.
Cover each pie by placing parchment paper or aluminium foil over it and then put something to keep the crust from rising too much while in the oven and for it to keep its shape. It could be uncooked rice, beans, etc.
Bake at 350°F (180°C) for 15 minutes, then take the paper and the rice or beans away, and keep baking them on their own for 5 more minutes.
Take them out of the oven and put them aside until needed.
For the filling:
In a big pot, put enough water to boil. Meanwhile, peel the sweet potato and shop it in pieces, and once the water is boiling put the pieces in it to cook.
Once the sweet potato is fully cooked (you´ll know it when a fork easily slides into it) take the pieces out of the water and place in a bowl to then mash them. Then, quickly, while the sweet potato is still hot, stir in the butter.
Now stir in the sugar and the egg. Then the evaporated milk, vanilla and heavy cream.
Lastly add in the ground cinnamon, nutmeg, ginger, salt and flour.
For baking:
Pour the mixture in the 4 pie pans.
Bake at 350°F (180°C) for 40 to 50 minutes. The pies wull be ready when the filling starts to dry around the edges but it´s still wiggly in the center.