Boil the sweet potatoes whole with skin on until fork tender, about 40 to 50 minutes. Cool them under running water and peel them.
If you are using a bought crust, thaw that out. If making your own crust, go ahead and make while the sweet potatoes are cooking, then line a pie dish with the crust and set aside.
Preheat your oven to 180 C (350 F).
Place the sweet potatoes in a pot and using a potato masher, mash them up well. Add remaining ingredients except for obviously, the crust :)
Pour the mixture into the prepared crust and bake for 50 to 60 minutes or until a knife or toothpick inserted in the center comes out clean. As the pie cooks it will puff up then sink down as it cools, perfectly normal.
Allow the pie to cool completely, break out the whipped topping, cut, serve, and enjoy.