Place a 9 inch cast iron skillet into your oven and preheat it to 400 degrees Fahrenheit. In a large bowl whisk together the flour, cornmeal, baking soda, and salt.
1 1/2 cups buttermilk, 1 1/2 cups all purpose flour, 1 1/2 cup cornmeal, 3/4 teaspoon baking soda, 1/2 teaspoon table salt
In another bowl whisk together the buttermilk, eggs, and oil.
2 eggs, 1/2 cup vegetable oil
Gently fold the wet ingredients into the dry ingredients until just combined.
Take the cast iron skillet out of the preheated oven and melt 1 tablespoon of butter in it.
1 tablespoon unsalted butter
Pour the batter into the prepared pan. Bake for 20 to 30 minutes. At the end of the baking time, the center should be puffed up and bounce back when you push down on it gently. The edges will be golden and a toothpick inserted into the center of the bread will come out clean.