Cornbread (American South)

This Southern cornbread is made totally from scratch, and is not sweet.
1 cup yellow cornmeal, fresh and preferably stone-ground
1 cup all-purpose flour, unbleached
1 Tbsp. baking powder
¼ tsp. kosher or sea salt
¼ tsp. baking soda
1¼ cups buttermilk
1 large egg
1/3 cup corn or vegetable oil
1 Tbsp. unsalted butter
Preheat oven to 375°F (190°C/170°C fan, Gas Mark 5).
In a bowl, blend together cornmeal, flour, baking powder, and salt.
In a separate bowl, mix together baking soda and buttermilk. Add butter and 1 teaspoon oil into cast iron skillet and place in oven to heat for 5-7 minutes.
Beat egg and oil together. Pour into cornmeal mixture. Add buttermilk mixture and blend until batter comes together. Don't over mix.
Remove the skillet from the oven and swirl butter to make sure it covers the pan.
Pour batter into skillet and bake in the preheated oven for 25 minutes or until golden brown on top.
Slice into wedges.
Makes 8 servings.