Step 1: Preheat your oven to 400°F (200°C). Grease a 9x13 inch baking dish or a 10-inch cast iron skillet with butter or shortening. If using a cast iron skillet, place it in the oven while it preheats to get it nice and hot.
Step 2: In a large bowl, whisk together the cornmeal, all-purpose flour, granulated sugar, baking powder, baking soda, and salt until well combined and no lumps remain.
Step 3: In a separate medium bowl, whisk together the buttermilk, melted butter (ensure it's not too hot), and eggs until the mixture is smooth and evenly combined.
Step 4: Pour the wet ingredients into the dry ingredients. Stir gently with a spatula or wooden spoon until just combined. Be careful not to overmix; a few lumps are perfectly fine and will lead to a more tender cornbread.
Step 5: Carefully remove the hot baking dish or cast iron skillet from the oven. Pour the cornbread batter evenly into the hot dish. The hot pan will help create a beautifully crispy bottom crust.
Step 6: Bake for 20-25 minutes, or until the cornbread is golden brown on top and a wooden skewer or toothpick inserted into the center comes out clean. Baking time may vary slightly depending on your oven.
Step 7: Remove the cornbread from the oven and let it cool in the dish for 5-10 minutes before slicing and serving warm. This brief cooling period helps the cornbread set and makes it easier to cut into perfect pieces.