Preheat the oven to 350°F. Lightly grease a 2-quart baking dish (an 11 x 7-inch dish or a deep square dish); set aside.
Heat the olive oil in a large skillet or Dutch oven over medium-high heat.
Add the onion and bell pepper; cook and stir just until the onion is translucent and the bell pepper is tender, about 5 minutes.
Reduce the heat to low, add the barbecue sauce, and simmer until the sauce thickens slightly (about 1-2 minutes). Stir in the frozen corn and the pulled pork. Taste the pork mixture and season with salt and pepper to taste.
Spread the pork mixture in an even layer in the bottom of the prepared baking dish. Sprinkle with ½ cup of the grated cheese.
In a separate bowl, prepare the cornbread batter according to the package directions.
Stir in the remaining ½ cup of grated cheddar cheese.
Spread the cornbread batter over the pork mixture. I like to do this by using a large spoon to dollop the batter all over the top of the casserole. Then use the back of the spoon to gently spread it around until it covers most of dish.
Bake the casserole for 30-35 minutes, or until the crust is golden brown and cooked through. Let stand for about 5-10 minutes before serving.
