Preheat your cast iron skillet (or metal cake pan) by placing it into the oven and setting the temperature to 350℉.
Gather all of your ingredients, along with 2 mixing bowls, a whisk and a rubber spatula.
In one of the mixing bowls, stir together the flour, cornmeal, baking powder, baking soda and salt. Set aside.
In a second mixing bowl, whisk together the milk, egg, maple syrup and olive oil.
Combine the dry and wet ingredients together, stirring until the mixture comes together, and the texture appears like a thick, grainy batter with no lumps or traces of flour.
Stir in the jalapeños and the cheddar cheese, reserving about a tablespoon of jalapeños to sprinkle on top before baking.
Once the oven has come up to temperature, and with your tablespoon of butter handy, carefully remove the skillet (or pan) from the hot oven. Grease the bottom of the skillet with butter until fully melted.
Pour the prepared cornbread batter into the skillet, sprinkle the reserved jalapeños evenly over the surface, and then carefully place the skillet back into the hot oven. Bake for 20-25 minutes, until the cornbread is golden brown, and a toothpick inserted into the center comes out clean. Slices can be cut into wedges, or squares, as desired.