Preheat oven to 450 and put 4 tablespoons Crisco in the cast iron skillet, place in oven for the Crisco to melt.
In a large bowl mix:
1.5 cup corn meal
3 tablespoons white flour
1 teaspoon baking soda
1 teaspoon baking powder
1 teaspoon kosher salt
In a smaller bowl pour in 2 cups buttermilk, whisk in 1 large egg.
Once the oven temp. reaches 450 mix the wet and dry ingredients, the batter will be thick, remove the skillet (wearing decent oven mitts) and swish the melted, smoking hot oil around to coat the skillet then pour the hot oil into the batter and stir it in.
Pour the batter into the skillet and bake for 25 minutes if you like a little bit of crust, 20 minutes if not, remove from oven and let sit for 5-10 minutes on a rack, the cornbread should fall right out of the skillet when you invert it.
If the buttermilk is a little sour all the better, if you don't have buttermilk sour some milk with a teaspoon of vinegar to the two cups milk, then add a slice of melted butter to the milk and it will be fine for baking.
I use dent white cornmeal, and prefer a medium course grind, I don't want a cake like texture.
The cast iron skillet is 9", a Wagner, and is dedicated for bread only.
You can do this with coals in a dutch oven, just don't burn it and check for done with a knife or stick method.
added: You can use other oils, but the solid criso works better than the liquid, bacon fat is good if you have it, but cut the salt to 1/2 teaspoon if using bacon fat (or not if sodium isn't an issue).