Heat the oven to 400 degrees. Place the butter in the cast iron skillet and put in the oven while it preheats, remove when butter has melted. Do not burn the butter.
In a large mixing bowl combine the cornmeal, flour, baking powder, salt and pepper. Mix in the buttermilk, eggs and sour cream. Carefully pour the melted butter into the mixture, leaving some in the pan so it is greased.
Place the skillet back in the oven so it is piping hot.
Fold in the cheddar cheese.
Remove the skillet from the oven and spoon the mixture into the hot cast iron skillet.
Place in the oven and bake 26-30 minutes. If you're using a cast iron skillet/pan with individual molds, cook 18-20 minutes.
Nutrition values per slice if cut into 8 large servings:
321 Calories, 19.6g Fat, 96.5mg Cholesterol, 653.6mg Sodium, 26.2g Total Carbohydrate, 1.3g Dietary Fiber, 1.7g Sugars, 10.5g Protein
Serving: 1slice (if cut into 12 small slices, Calories: 214kcal, Carbohydrates: 17.5g, Protein: 7g, Fat: 13g, Cholesterol: 64.3mg, Sodium: 435.8mg, Fiber: 0.9g, Sugar: 1.1g