Whisk together flour, cornmeal, baking powder, baking soda, and salt. 

In a food processor or blender, pulse together buttermilk, corn, eggs, ¼ cup honey, and ¼ cup oil until combined, 15–20 pulses (corn lumps will remain). 

Make a well in the dry ingredients and pour in wet ingredients into well. Using a rubber spatula, gently fold mixture just to combine (small pockets of flour are OK.)

Carefully remove cast-iron skillet from oven; pour remaining tablespoon oil into skillet, swirling to coat bottom of skillet.

Pour batter into skillet and smooth top with spatula. 

Carefully return skillet to oven and bake cornbread until golden on top and a toothpick inserted in the center comes out clean, 24–25 minutes.  

Microwave remaining 2 tablespoons honey, in a microwave-safe bowl, for 30 seconds on medium power. 

Brush warm honey over surface of warm corn bread; sprinkle with sea salt. Let cool 15 minutes.