Add clean sweet potato in a deep pot.

Cover with water.

Boil for 50-55 minutes or until soft.

Remove from the pot and run cold water over the potato.

Remove the skin.

Preheat the oven to 350 degrees.

Put the sweet potato in a blender, you must pulse it for at least 1 minute.

Scoop the puree potato into a large bowl.

Mix in the butter.

Using an electric mixer, add sugar, milk, eggs, pumpkin pie spice, cinnamon,
and vanilla.

Beat on medium speed until well blended.

Pour the filling into the unbaked pie crust.

Bake at 350 degrees for 55-60 minutes.

Stick a toothpick in the center of the pie to see if it is fully baked.

If not, return it to the oven and continue to bake.

Check every 5 minutes until completely baked.

Set aside to cool slightly.

Serve with a dollop of Cool Whip.