Preheat your oven to 400°F.

Place your cast iron skillet in the oven to heat up while you prepare the batter.

In a large bowl, whisk together the cornmeal, flour, baking powder, salt, and sugar.

In a separate bowl, mix together the milk, oil or melted butter, and egg until smooth.

Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix.

Carefully remove the hot skillet from the oven using oven mitts.

Add 1 tablespoon of butter to the skillet and swirl it around to coat the bottom and sides.

Immediately pour the batter into the hot, greased skillet. You should hear a light sizzle.

Place the skillet back into the oven.

Bake for 20–25 minutes or until the top is golden brown and a toothpick comes out clean.

Let the cornbread cool in the skillet for 5 minutes before slicing and serving.