Preheat the oven to 350 degrees F
Bring the sweet potatoes (still in their skin) to a boil in a covered pan with 2 - 4 cups of water. Cook until tender (when a knife inserts easily.) Set potatoes aside to cool.
While the potatoes are cooling prepare your pie crust.
Once the potatoes are cooled enough to handle peel them and dump them in a large bowl. Mash with a potato masher or something similar.
Mix in both sugars, butter, eggs, vanilla and spices. Whisk together for 4 - 5 minutes until well blended.
Mix in the milk and whisk for another minute or two until thoroughly blended.
Pour the filling into the pie crust and bake for 1 hour.
The pie is done when there is little to no jiggle to the filling.