Ultimate Taco Stuffed Pepper Casserole

Preheat the oven to 375°F (190°C).
Heat olive oil in a large oven-safe skillet or pan over medium heat. Add diced onion and bell peppers, sautéing until softened, about 5 minutes.
Add ground beef to the skillet. Season with salt and pepper, cook until browned, breaking it up as it cooks. Drain excess fat.
Stir in taco seasoning, diced tomatoes with their juice, frozen corn, black beans, uncooked rice, and water or broth.
Bring mixture to a boil. Then reduce heat to low, cover, and simmer for 18–20 minutes until rice is tender and liquid is absorbed.
Sprinkle shredded cheese evenly over the casserole.
Transfer skillet or pour mixture into a greased 9x13-inch baking dish if not oven-safe.
Bake uncovered for 10 minutes, or until cheese is melted and bubbly.
Remove from oven and let rest for a few minutes before serving.
Serve topped with optional sour cream, cilantro, avocado, or jalapeños if desired.