Scrub sweet potatoes and poke several holes in them with a fork. Place them in a baking dish or line an oven rack with aluminum foil.
Bake at 425°F (220°C) 40-50 minutes. When cool enough to handle, scoop 2 cups of sweet potato out of the skin.
Press your favorite pie crust dough into a 9-inch pie pan. Line with foil and fill with pie weights.
Bake at 425°F (220°C) for 12-15 minutes, until the edge of the crust just begins to turn golden brown.
Reduce the temperature to 350°F (180°C). Remove the pie weights and bake an additioanl 5 minutes. Remove the crust from the oven and set aside to cool while you make the filling.
Mix potatoes and butter together using a potato masher or an electric mixer. Add remaining ingredients and mix well.
Pour into a pie shell and place a pie shield or foil over the curst edges. Bake at 350°F (180°C) for 40-50 minutes. The pie should jiggle just a little in the center. A knife inserted into the edge of the pie should come out clean.
Cool at room temperature for 2 hours and then chill completely in the refrigerator.