This cornbread is best baked in a 10-inch cast-iron skillet but if you don't have one, a Pyrex dish will do just fine. If you halve this recipe, use an 8-inch square dish; if not, use a 9x13-inch dish or pan.
Preheat oven to 450°F.
Put the bacon drippings in your baking dish or skillet and let them melt while the oven is preheating and you're mixing up the batter.
Beat the eggs in a medium bowl until frothy. Add the corn meal, salt, baking soda and baking powder, and stir to thoroughly combine. Add the buttermilk and stir well. Remove the hot pan from the oven. Swirl the pan to make sure it is coated with melted bacon drippings, and pour the bacon drippings into the batter. Stir well to combine.
Pour the batter into the pan, and bake 20 to 25 minutes. Cornbread will begin to pull away from the sides of the pan.
Note: Cornbread batter should be mixed, poured and baked quickly. As soon as the leavening ingredients (that would be the baking soda, baking powder and buttermilk) are combined, the chemical action that makes the cornbread rise is sparked. No need to hurry; just don't mix up the batter and then make a phone call before you pop it in the oven.