Preheat oven to 350 F degrees and position rack to middle of oven. Butter an 8-inch cast iron skillet. (Can use an 8-inch baking dish, but the cooking time will differ. Watch for over-browning.) Slice the jalapeno into 1/8 inch thick rounds.
Put the ingredients for the cornbread into the bowl of a food processor in order. Process the ingredients until the form a sticky dough.
Scrape the dough into the prepared skillet and gently spread to edges and top with jalapeno slices.
Bake for 25-30 minutes or until the top is lightly browned. Remove from the oven and let cool for 10 minutes before running a sharp, thin knife around the edge and slicing to serve.
Store leftovers in an airtight container in the refrigerator. Reheat in the microwave or place on a sheet pan and reheat in a 300 F oven until warmed through (about 15 minutes).