Prepare sweet potatoes ahead: bake at 375º F for 75 minutes wrapped in foil, then allow to cool, peel, and mash with a potato masher or fork.
Preheat oven to 425ºF. with an oven-proof glass baking dish or pie pan or ramekin with water on a shelf lower than where you will put the pie.
Fit pie crust into a deep dish glass pie plate and flute edges.
Whisk together the sugar, salt, ginger, cinnamon, nutmeg and cloves.
Whisk in the beaten eggs and mashed sweet potatoes.
Gradually stir in the evaporated milk until filling is smooth.
Place pie plate on a baking sheet and bake at 425°F for 15 minutes, then reduce heat to 350ºF and continue baking for another 40-50 minutes or until a knife can be slipped in and out of the pie center without wet filling clinging to it.
Cool pie completely before slicing and serving.
Serve with whipped cream as desired; refrigerate unused pie portions, covered with plastic wrap.