southern cornbread recipe

**Ingredients:** - 1 cup yellow cornmeal - 1 cup all-purpose flour - 1/4 cup granulated sugar (optional, for a sweeter cornbread) - 1 tablespoon baking powder - 1/2 teaspoon baking soda - 1/2 teaspoon salt - 1 cup buttermilk - 2 large eggs - 1/4 cup unsalted butter, melted - 2 tablespoons vegetable oil (for the skillet)