Preheat the oven to 400F.
Stir together the flour, cornmeal, baking soda, and salt in a large bowl.
In another bowl, beat the egg and buttermilk until combined, then mix in the melted butter and bacon drippings.
Quickly stir the buttermilk mixture into the dry ingredients.
Spoon the batter into a greased 9x9-inch square baking dish, smoothing the top.
Bake at 400°F for about 20 minutes, or until the edges turn golden brown and a toothpick inserted in the center comes out clean.
Let cool for 5 to 10 minutes before serving.
Preheat the oven to 425° with a 9-inch cast iron skillet in it.
Mix the cornbread batter as directed above.
Carefully remove the skillet from the oven (use pot holders it will be hot!) and add a tablespoon or two of butter or bacon grease.
Move the butter quickly around the skillet with a spatula to coat the entire surface.
Spoon the batter into the prepared skillet and bake at 375° for 20 minutes or until the interior is 200° on an instant read thermometer.
Cool for at least 10 minutes and serve right from the pan.
