Preheat oven to 350°F.
Boil sweet potatoes in their skins for 45-50 minutes or until soft. Run them under cold water then peel and discard skins.
Blend potatoes in a blender for about one minute to make sure all fibers are broken and potatoes are smooth. Place in a bowl, add butter and mix well. Add sugar, milk, eggs, cinnamon, vanilla extract and nutmeg, and beat on medium speed with a hand mixer until smooth. (Don't beat too much or it will be a soup! You want some consistency.)
Pour filling into pie crust and bake for approximately 50-60 minutes, or until knife inserted in the center comes out clean. Let it cool before cutting. Enjoy!