Make the crust: Put the flour, sugar, and salt in a food processor; pulse to combine. Add the butter and shortening; pulse until the mixture resembles coarse cornmeal. Transfer to a mixing bowl. Working quickly, gradually add the cold water, tossing and stirring with a fork until the dough just begins to come together. Shape into a disk, wrap in plastic, and chill for several hours or overnight. Heat the oven to 400°F. Roll the dough disk into a 14-inch round that's 1/8 inch thick; ease it into a 9-inch pie pan, trim a 3/4-inch border, and crimp an edge crust. Line the shell with foil, fill it with dried beans or pie weights, and bake until just set, 12 to 15 min. Remove the beans and continue cooking until light golden, about 15 min. Let the partially baked pie shell cool.
Make the filling: Raise the oven temperature to 425°F. Pierce the sweet potatoes at each end with a fork and set them on a foil-lined baking sheet. Roast the potatoes until soft, about 1 hour, turning them halfway through. Cool, peel, and force them through a food mill or a coarse-mesh sieve. You should have about 2 cups of purée. Lower the oven to 350°F. Combine the purée with the melted butter, vanilla extract, eggs, yolk, cream, brown sugar, bourbon, salt, nutmeg, cinnamon, cloves, and pepper. Whisk until blended and smooth. Pour the filling into the baked shell and bake until the filling is just set, about 50 minutes. To test, nudge the rim of the pie plate-the center of the pie should quiver slightly and still be glossy and wet looking. Let cool and then chill thoroughly before serving.