Preheat the oven to 350℉. Place a 10 inch cast iron skillet into the oven while it preheats.
Add the all purpose flour, cornmeal, baking powder, baking soda, and kosher salt into a bowl. Whisk until the ingredients are evenly combined.
In a separate bowl, add in the granulated sugar, honey, eggs, and melted butter. Whisk until combined. Pour in the vegetable oil and buttermilk then mix. Add the wet ingredients into the bowl of dry ingredients. Whisk until the ingredients are combined into a batter.
Remove the hot cast iron pan from the oven. Place the remaining tablespoon of butter into the cast iron. Swirl the butter around as it melts to coat the pan. Pour the cornbread batter into the cast iron and smooth out the top.
Bake it in the oven for 30-35 minutes. When a toothpick is inserted into the center it should come out clean. My cornbread took about 33 minutes. Tent the cornbread with foil if the top starts getting too brown. Allow it to cool until warm then serve with the honey butter. If desired, top with an additional drizzle of honey and flakey salt. Enjoy!