Preheat to 350°F.

Wash, dry, and core the bell peppers using a pepper corer.

Add the olive oil to a large skillet and heat to medium high. Add the yellow onion and sauté 3 minutes, stirring occasionally. Add Anaheim pepper, and sauté another 2 to 3 minutes. Add garlic, chili powder, and salt, and sauté until garlic is fragrant, about 2 to 3 minutes.

Add 1/2 cup of the enchilada sauce, the cooked rice, corn, and black beans. Stir well and cook just until well combined and rice has absorbed most of the enchilada sauce, about 1 to 2 minutes. Remove from heat.

Stuff each pepper with the rice and vegetable mixture, filling each cavity to the top. Top each pepper with grated cheese and place peppers in an 8-inch by 8-inch baking dish. The peppers should fit nice and snug in the baking dish and should hold each other up.

Pour the remaining enchilada sauce and the water around the peppers, so that they’re sitting in a sauce bath. Place on the center rack of the oven and bake for 30 to 40 minutes, until cheese has melted and the tops of the peppers have softened.

Remove peppers from the oven and allow them to cool 10 minutes before serving.