1. Preheat oven to 400°. Lightly grease an 8-inch cast-iron skillet, and heat in oven 5 minutes.
2. Meanwhile, whisk together first 5 ingredients in a bowl; whisk in melted butter. Add eggs and buttermilk, whisking just until smooth.
3. Pour batter into hot skillet. Bake at 400° for 30 to 33 minutes or until golden brown.