Make the Creamed Corn. Remove the kernels from the fresh corn with a sharp knife over a large bowl or rimmed baking sheet. Some may fly so have enough space for the kernels to fall.
Add the corn and the remaining “Creamed Corn” ingredients to a medium saucepan over medium to medium-high heat. Gently simmer for approximately 10 to 15 minutes. Some liquid will evaporate and the mixture will thicken. Taste and adjust any salt, pepper, and/or sugar.
Pour the Creamed Corn into a deep medium bowl and cool.
Using an immersion blender, puree about half of the mixture. Or, you can place half of the cooled corn into a food processor or blender and gently pulse to a coarse texture.
The Creamed Corn can be made in advance, well-covered and refrigerated for up to 2 days. Before using, allow the Creamed Corn to come to room temperature.
Make the Cornbread. Preheat the oven to 400 degrees F. Place a large (12”) cast iron skillet into the oven to heat while the oven preheats.
In a large bowl, mix the cornmeal, flour, sugar, baking powder, and salt. Add the shredded cheeses and jalapeno, if using, and toss. Set aside.
In a medium bowl, combine the Creamed Corn, buttermilk, eggs, and oil. Set aside. You will combine the dry and wet ingredients just before placing the pan into the oven.
Once the oven is preheated, protecting your hands with oven mitts or dish cloths, remove the cast iron skillet onto a heat-safe surface. Add the 2 tablespoons of butter and swirl the pan to cover the bottom and sides of the skillet.
Add the wet ingredients to the dry ingredients and stir to combine. Do not overwork the batter. Stir just until all the ingredients look combined and there are no pockets of flour.
Pour the batter into the hot skillet, scraping the bowl to get all the deliciousness in there. It’s fine if some of the melted butter finds its way to the top of the mixture.
Top with jalapeno slices if desired.
Carefully place the hot skillet back into the oven and bake until the cornbread is nicely browned and risen, approximately 20 to 25 minutes. It’s okay if it has domed a bit in the middle. Check for doneness - a toothpick inserted in the middle comes out with just a few crumbs or clean.
Remove the cornbread from the oven and let it cool for about 10 minutes before cutting into it. (You can invert the cornbread onto a cutting board or plate, or just cut and serve from the cast iron skillet.)
Serve very warm with butter.
Any leftovers (yeah, right) should be covered well and refrigerated for up to 5 days, or frozen up to 3 months.