1 store-bought pie dough
2-2 1/2 large sweet potatoes or 2 cups pureed sweet potatoes
2/3 cup granulated sugar
1 1/2 teaspoons pumpkin pie spice
1/2 teaspoon freshly grated ginger root
1/4 teaspoon salt
1 1/2 cups milk
3 large eggs
1/2 stick butter, melted and cooled
1 tablespoon vanilla extract
Pre-heat the oven to 400°F. Scrub the sweet potatoes so the skin is clean and wrap them tightly in foil. Use a fork to prick through the foil into the skin of each potato. Place the potatoes onto a baking sheet and roast in the center of the oven until tender, about 1 hour. Allow the potatoes to cool before removing the skin and placing into a food processor. Process the potatoes until they are smooth and creamy.
Turn the oven temperature to 450°F. Roll the out the dough onto a floured surface until it is big enough to fit a 9-inch pie plate. Place the dough into the pie plate and set in the refrigerator until you make the filling.
Place 2 cups of the pureed sweet potatoes into a large bowl along with sugar, pumpkin pie spice, ginger, salt, milk, eggs, butter and vanilla extract. Whisk until well combined. Place the prepared pie plate onto a rimmed baking sheet and pour the filling into the prepared pie dough. Bake at 450°F for 10 minutes, then turn the temperature down to 325°F and cook the pie for 1 hour more. Remove the pie from the oven and allow the pie to cool completely before cutting.