Preheat oven to 450°.
Pour oil into a 9-inch cast-iron skillet. Place skillet in oven for 10 minutes.
Combine the cornmeal, salt, baking powder, and baking soda in a large bowl. Combine buttermilk, pepper, and egg, stirring with a whisk. Add egg mixture to cornmeal mixture, stirring just until moist. Remove pan from oven. Tip pan to coat bottom and sides with oil; carefully pour excess oil into batter, stirring to combine. Pour the batter into pan, spreading evenly. Bake at 450° for 15 minutes or until a wooden pick inserted into center comes out clean. Let stand 5 minutes before serving.