For the gingersnap crumb crust:

1. Preheat oven to 325ºF /160ºC
2. In a food processor, ground cookies. Don’t wash the food processor.
3. Add melted butter and pulse until it’s like wet sand.
4. Dump it onto a glass 9-inch (24cm) pie dish. With the back of a spoon, a measuring cup and your hands, evenly pat the crumbs onto the bottom and sides of the pan. Try to make it as even as possible and make sure it’s pressed.
5. Bake for 10 minutes. Reserve on a wire rack while you make the filling.
6. Leave the oven on.

For the filling:

1. Pierce sweet potatoes with a fork 5 or 6 times each.
2. Cook in the microwave oven for about 5 to 7 minutes, or in an electric oven for about 45 minutes, or until very soft when pierced with a fork.
3. Let cool until you can handle them, cut in half, and scoop out the pulp. Let it cool down until it's at room temperature. 
4. In the same processor you used for the crust, put the sweet potatoes, salt, cinnamon, ginger, nutmeg, allspice, sugar, and pulse until it’s well mixed. Don’t worry if the potatoes aren’t very smooth.
5. Add the eggs, condensed milk, vanilla, and mix until smooth.
6. Add butter and pulse until it’s an even batter. It will be quite liquid.
7. Pour the filling carefully into the baked crust, sprinkle the pecans on top, and return to the oven for about 30 minutes, until the center is set.
8. Let cool on a cooling rack to room temperature and serve.