How to Make It
Preheat oven to 400°F. Place a 9-inch cast-iron skillet in the oven to preheat with the oven.
In a large mixing bowl, whisk together buttermilk, eggs, 5 Tbsp. melted butter, and salt. Stir in baking powder, baking soda, and cornmeal until fully incorporated. The batter should be loose but without any lumps.
Remove cast-iron skillet from the oven and pour in the remaining 2 Tbsp. melted butter, carefully swirling the skillet to coat it in butter. Pour batter into skillet and bake until golden brown and until a toothpick inserted into the center of the cornbread comes out clean, 38 to 40 minutes.
If you prefer sweetened cornbread, stir in 2 Tbsp. granulated sugar in Step 2. This cornbread is also easy to customize by adding ingredients to the batter. Feel free to stir in cooked pieces of bacon, fresh chives, jalapeño pepper pieces, shredded cheese, or fresh corn kernels.