Heat oven to 425ºF and place a 10-inch cast-iron skillet in the middle of the center rack.
Whisk the cornmeal, salt, sugar, baking powder, and baking soda together in a large mixing bowl.
In a medium bowl, whisk together 1 cup of the buttermilk, the eggs, and creamed corn.
Add the wet ingredients to the dry ingredients and whisk to combine. If the batter seems a little thick, add a bit more of the buttermilk.
Pour the oil into the hot skillet and carefully swirl to coat. Pour in the batter and jiggle the pan to evenly distribute. Bake until the bread is golden brown and springs back when touched, or a digital instant-read thermometer inserted in the center of the bread registers 200 to 205°, about 20 minutes.
Remove from the oven and let cool for several minutes. Place an inverted dinner place on top of the bread and flip it out of the skillet.
Serve with butter.