Yam-sweet potato pie

It's that time of year; and this is the perfect holiday dessert !Enjoy 
 Ingredients: 2 medium sweet potatoes - 1 medium yam - 1/2 cup butter, softened - 1 cup white sugar - 1/2 sour cream - 2 eggs - 1/2 teaspoon ground nutmeg - 1/2 teaspoon ground cinnamon - 1 teaspoon vanilla extract - 1 9 inch lightly baked pie crust
Prep: Boil sweet potatoes whole in skin for 40 to 50 minutes, or until done. Run cold water over the sweet potatoes; remove the skin. Break apart sweet potato in a bowl. Add butter, and mix well with mixer. Stir in sugar, milk, eggs, nutmeg, cinnamon and vanilla. Mix or beat on medium speed until mixture is smooth. Pour filling into an unbaked pie crust. Bake at 350 degrees for 55 to 60 minutes