Mexican Cornbread

2 cups self-rising cornmeal mix
1 1/2 to 2 cups milk
1/4 cup sugar
1 large egg
1/4 cup oil (I use avocado, but vegetable or canola is fine.)
1 (14.75-ounce) can creamed corn
2 cups freshly shredded cheese (We prefer pepper Jack or Colby Jack.)
1/4 cup chopped pickled jalapeños
1/4 cup finely diced onion (optional)
Coat a large cast iron skillet with oil. Place inside oven, then heat oven to 425 F. In a large mixing bowl, combine all ingredients, using 1 1/2 cups milk to start. If it seems too thick, add more milk. Once the skillet is heated well, carefully take it out and pour in the cornbread mixture. Return to oven and bake 20 to 25 minutes or until golden brown. Remove from oven and invert cornbread onto a plate quickly. This allows the crust to stay crisp. Cut and serve alongside chili, pinto beans or alone topped with butter. This cornbread also freezes well. To serve after freezing, allow the cornbread to thaw before heating in the oven for a few minutes.