Prepare the peppers. Use a small knife to cut off the top of each bell pepper. Season the inside of each pepper with salt and pepper. Place peppers into a large baking dish (or a cast iron pan like I did), wedging them together as needed to fit in one layer. Set aside.
Gently, cut the stems from the tops and discard them. Chop the tops to use in the filling.
Pre-heat the oven 375 F degrees.
To make the filling: Heat oil in a large pot over medium heat. Add in the onion, chopped peppers, ground cumin, ground coriander, salt and pepper. Cook, stirring frequently, until onions and peppers are softened, 5-7 minutes.
Add in the meat. Using a wooden spoon break large pieces and cook until everything is combined and meat is cooked, 6-8 minutes.
Stir in the garlic and cook for 30 seconds.
Stir in the tomatoes, black beans, and corn. Put the lid on, bring it to a boil, and then let it simmer for 3-4 minutes. Taste for seasoning and add in if needed.
Off the heat add in the cooked rice and chopped cilantro. Give it a gentle stir.
To assemble the peppers: Divide the filling amongst the peppers. Top each pepper with a generous amount of shredded cheese.
Fill the bottom of the pan with a cup of water and cover the peppers with aluminum foil (or parchement paper).
Bake in the oven until the peppers are softened and the filling is heated through for about 50-55 minutes.
If preferred, garnish with cilantro and serve.