Preheat Oven and Prepare Skillet: Preheat your oven to 375°F (190°C). Place the butter into a large 12-inch cast iron skillet and set the skillet in the oven to melt the butter. This should take 5 to 13 minutes, depending on your oven—watch closely toward the end. The butter should bubble and begin to brown slightly but not burn.
Mix Dry Ingredients: While the butter melts, combine the cornmeal, flour, salt, baking powder, and baking soda in a large mixing bowl. Stir until everything is evenly distributed, then set aside.
Whisk the Wet Ingredients: In a separate medium bowl, whisk the eggs with the honey or maple syrup until smooth and fully incorporated. Add the milk and whisk again until the mixture is well blended.
Combine Wet and Dry Mixtures: Pour the wet mixture into the dry ingredients and gently stir just until combined. It’s okay if the batter still has a few lumps—we’ll stir again after adding the butter.
Add Melted Butter to Batter: Using oven mitts, remove the skillet from the oven once the butter has melted and browned slightly. Carefully swirl the butter around to coat the bottom and sides of the pan. Then pour all the butter into the batter and stir until just incorporated.
Transfer Batter to Hot Skillet: Pour the batter into the hot, butter-coated skillet. Use a spatula to scrape down the sides of the bowl so you don’t waste any of the mixture. Smooth out the top gently.
Bake Until Golden and Set: Return the skillet to the oven and bake for 25 to 30 minutes, or until the edges are golden brown, the center is firm and springy, and a toothpick inserted comes out with just a few moist crumbs.
Cool Briefly and Serve: Remove the skillet from the oven using mitts and let it rest on a cooling rack for at least 5 minutes before slicing. Serve warm with a pat of butter, a drizzle of honey, or your favorite jam.