Preheat oven to 400°. Place butter in bottom of a 9-inch cast-iron skillet, and place skillet in oven to heat.
In a large bowl, whisk together cornmeal mix and salt. Add buttermilk and egg, stirring just until combined. Remove skillet from oven, and swirl to coat bottom and sides of pan with melted butter. Pour batter into hot pan.
Bake for 20 to 25 minutes or until cornbread is golden brown and begins to pull away from sides of pan. Serve immediately.
Recipe by Paula Deen Magazine at https://pauladeenmagazine.com/old-fashioned-cornbread-recipe/