Preheat the oven (with your seasoned cast iron skillet inside) to 400°.
In a bowl mix 1 cup of flour, 1 cup of cornmeal, 2/3 cup of sugar, 1 tspn of salt, and 3 1/2 tspn of baking powder. Whisk all dry ingredients before adding anything wet.
Add 1 large egg, 1/3 cup of olive oil, and 1 cup of buttermilk to dry ingredients.
Whisk everything together until you get a smooth pancake mix texture. It should not be too thick, but not too runny either.
Carefully pull your HOT skillet out of the oven and drizzle the bottom with a touch of olive oil. Shake it around until the bottom of the skillet is thinly, and evenly covered.
Pour the cornbread mixture slowly and evenly into the HOT skillet. You will see the edges begin to sizzle and cook.
Put the lid on (or cover with foil) and place in the oven for 10-15 minutes. Check on it after 10 minutes and go from there, ovens vary.
Remove the lid and pop back in the oven UNCOVERED for another 10-15 minutes, or until golden brown on top.