Preheat your oven to 375 degrees F. Grease the bottom and sides of a 10-inch cast iron skillet with 1 teaspoon butter (use more if needed).
Place the skillet in the oven as it preheats while you're preparing the batter.
Whisk together cornmeal, baking soda, salt, and baking powder in a large mixing bowl.
In a separate medium bowl, whisk buttermilk, eggs and melted butter until combined.
Pour the wet mixture into dry mixture and stir until just combined (do not over-mix).
Using oven mitts, carefully remove the hot skillet from the oven. Pour the batter into the skillet (you should hear it sizzle).
Using oven mitts, carefully return the hot skillet to the oven and bake for 20 minutes, or until edges are browned, and a toothpick inserted in the center is removed clean.
If additional browning is desired on top, broil on high for 1 to 2 minutes, watching carefully.
Cool 15 to 20 minutes before slicing.