Coat bottom and sides of a 10 inch cast iron skillet with oil; heat in a 450 oven for 10 minutes.
Whisk together buttermilk and egg. Add cornmeal, sitrring well.
Stir in baking powder, baking soda, and salt. Pour batter into
hot skillet.
Bake at 450 for 15 minutes. Serve with butter.