Preheat oven to 350°F. Place frozen pie shell onto a baking sheet to move easily in and out of the oven,
In a medium-size mixing bowl whisk together buttermilk, butter, vanilla, eggs, sugar, flour and nutmeg until fully combined. Add coconut, mixing thoroughly.
Pour the filling evenly into crust. Place into the oven. Bake for 30 minutes, then cover the edges with foil.
Bake for an additional 20-30 minutes or until the center is set when gently shaken.
Remove the pie from the oven to a cooling rack to cool completely.
Serve topped with fresh whipped cream or cool whip.