Coat bottom and sides of a 10-inch cast-iron skillet with bacon drippings; heat in a 450° oven for 10 minutes.
Whisk together buttermilk and egg. Add cornmeal, stirring well.
Stir in baking powder, baking soda, and salt. Pour batter into hot skillet.
Bake at 450° for 15 minutes. Serve with butter.
Note: This recipe is adapted from Hoppin' John's Lowcountry Cooking by John Martin Taylor.