3 boiled sweet potatoes, mashed
1 thin pie crust
1 Tablespoon vanilla flavoring
1 teaspoon nutmeg
1 teaspoon cinnamon

Pour mashed sweet potatoes into mixing bowl.

Add butter, mixing until butter has completely dissolved. 

Add egg yolks, mixing until the yolk has disappeared.

Mix  potatoes, butter, and yolks thoroughly.

Add sugar and mix until sugar particles have dissolved. 

Combine cinnamon, nutmeg, and vanilla flavoring.

Add spice mixture to sweet potato mixture.  Mix until visible particles have disappeared.

Add milk. Stir for three minutes.

Pour mixture into thin pie crust. 

Bake at 350 degrees for 35 to 40 minutes, or until pie crust has browned. 

Cool for 15 minutes.