- 1 (9 inch) unbaked pie crust
 - 2 cups cooked and mashed sweet potatoes
 - 2 tablespoons butter, softened
 - 2 eggs, beaten
 - 1 cup white sugar
 - 1 tablespoon all-purpose flour
 - 1/2 teaspoon salt
 - 1/2 cup buttermilk
 - 1/4 teaspoon baking soda
 - 1 teaspoon vanilla extract
 
- Preheat oven to 350 degrees F (175 degrees C).
 - Mix together mashed sweet potatoes, butter or margarine, and eggs. In a separate bowl, mix together sugar, flour, and salt. Mix in spices if desired. Add to sweet potato mixture and stir well.
 - Mix together buttermilk and baking soda. Add to sweet potato mixture and stir well. Mix in vanilla extract. Pour filling into pastry shell.
 - Bake in preheated oven for 70 minutes, until set in center.