"My mother-in-law passed down this very old recipe to my wife. The first time she made it, I was completely surprised. I had never heard of it, and I've been unable to find anything else quite like it. You can fix this as a side dish to a meal, or make it into muffins for snacks. Either way, you'll be pleasantly surprised."
Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13-inch baking dish with cooking spray.
Cook sausage and onion in a large skillet over medium heat, stirring until sausage is crumbly and no longer pink, about 5 minutes. Drain on paper towels.
Mix cornmeal, flour, salt, and baking soda together in a large bowl.
Whisk buttermilk, oil, and eggs together in a small bowl. Add to the cornmeal mixture, stirring just until moistened. Stir in sausage mixture, black-eyed peas, Cheddar cheese, corn, green chile peppers, and pickled jalapeno peppers. Pour batter into the prepared baking dish.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 1 hour.