1. Preheat oven to 425°F. Place cast iron skillet in the oven while it preheats.
  2. In a large bowl, mix together all the dry ingredients. In a separate bowl, whisk eggs and mix in whole milk, buttermilk, and butter.
  3. Pout the liquid into the dry ingredients until and mix until just combined. Fold in the bacon.
  4. Remove the cast iron skillet from the oven and add bacon grease, coating the bottom and side of the pan.
  5. Pour the batter into the greased skillet and place in the oven. Bake for 20-25 minutes or until center is set.
  6. Allow to cool and serve.