Cook the sweet potatoes:

1. To bake the sweet potatoes. Prick sweet potatoes all over with a fork and place on a large half sheet baking pan. Bake in a 400F preheated oven for 45 to 50 minutes until tender. Let cool completely and remove the skin. Mash it with a fork and set aside.
2. To boil the sweet potatoes. Place sweet potatoes in a large pot and cover with at least 1-inch of water. Bring to a boil and cook over medium heat for 30-35 minutes until tender. Let cool under running water and remove the skin. Mash it with a fork and set aside.
3. To pressure cook or cook in an instant pot.  Place 1 cup cold water and a steamer rack in the instant pot pressure cooker. Place sweet potatoes on the steamer rack. Switch to pressure cooking mode on manual high and seal the lid. Cook the sweet potatoes for 20-25 minutes until tender. Once the time is up, quick release pressure or wait until all of the steam has released and the valve has dropped. Let cool under running water and remove the skin. Mash it with a fork and set aside.

Make the sweet potato pie:

1. Preheat oven to 350 F.
2. In a large bowl, add cooked mashed sweet potatoes (or sweet potato puree), butter, cream, sugar, eggs, vanilla, cinnamon (or pumpkin pie spice), and salt. Mix well with an electric hand mixer or whisk to combine until smooth, about 1 minute.
3. Fit the uncooked pie crust on a 9-inch pie dish and slowly add in the sweet potato filling. Smooth out the top using the an icing spatula or the back of a spoon.
4. Bake for 55 to 60 minutes, or until a knife inserted into the center of the pie comes out clean. Note that the pie might puff up when first taken out of the oven, but it will sink down once it cools. Let cool completely, then serve.