Preheat oven to 450 degrees (with skillet in the oven).
Meanwhile, in a medium bowl stir together cornmeal, flour, sugar, salt, and baking powder.
In a second bowl add the egg and lightly beat.
To the egg add both the milk and buttermilk; mix well.
Add in baking soda and mix again.
Pour wet ingredients into dry and mix until just combined. Don't over mix; batter will still be a little lumpy.
Drizzle in melted shortening.
Carefully remove skillet from the oven and add in the butter. When butter is melted (put it back in the oven for a minute if need be) pour batter into skillet.
Bake 15-20 minutes until golden.
Recipe by Views From the Ville at http://viewsfromtheville.com/2015/04/17/skillet-cornbread-recipe/