Set a 9-inch cast-iron skillet in oven on middle rack; heat oven to 400°F (204ºC). 

Whisk together flour, cornmeal, baking powder, baking soda, and kosher salt in a large bowl. 

In a food processor or blender, pulse together buttermilk, corn, eggs, ¼ cup honey, and ¼ cup oil until combined, about 15 pulses (corn lumps will remain). 

Add buttermilk mixture to flour mixture and mix, using a rubber spatula, until mixture is just combined. 

Carefully remove cast-iron skillet from oven. Add remaining tablespoon oil to skillet and swirl to coat bottom and partially up sides (you can also use a pastry brush to do this). 

Pour batter into skillet and smooth top with spatula. 

Carefully return skillet to oven and bake cornbread until golden brown and a toothpick inserted in the center comes out clean with a few small crumbs, about 24–25 minutes.  

Microwave remaining 2 tablespoons honey, in a microwave-safe bowl until bubbling, 12–15 seconds.

Using a pastry brush, brush warm honey over surface of warm corn bread; sprinkle with sea salt. Let cool at least 20 minutes before cutting.