The suggested vegetables here are just that, a gentle suggestion. Mix it up depending on what's in season and fresh at the market. Make it taste good! This recipe will support about five cups of chopped vegetables. Any more and the batter doesn't hold together very well, and any less, it's not really vegetable corn bread. I like to use a variety of chiles and leave the seeds in the rings to give the corn bread some kick, but you could remove them or try chopped zucchini, yellow squash, or eggplant. If you use these more watery vegetables, you should parcook them first to remove some of the moisture (this could be as simple as zapping in the microwave and draining off the excess water). Make sure to seek out whole-grain, not self-rising cornmeal for the best corn flavor. It is also known as "nondegerminated." How's that for a word?
Put the oil in a large cast-iron skillet or ovenproof baking dish and heat in the oven until the oil is piping hot, about 10 minutes.
Meanwhile, in a bowl, combine the cornmeal, salt and baking soda. Add the okra, onion, corn, banana pepper and chiles and toss to coat. Set aside. In a large measuring cup, combine the buttermilk and egg. Add the wet ingredients to the dry and stir to combine.
Remove the heated skillet from the oven and pour the hot oil into the batter. Stir to combine, and then pour the batter back into the hot skillet. Bake until golden brown, about 35 minutes. Remove to a rack to cool slightly. Using a serrated knife, slice into wedges and serve warm.