Begin by preheating your oven to 375°F (190°C). Grease a 9x13 inch casserole dish with cooking spray or a small amount of oil to prevent sticking.
In a large skillet over medium heat, add the ground beef. Cook it, breaking it apart with a spatula, until it is nicely browned. Drain any excess fat if needed to keep the dish from being too greasy.
Once the beef is browned, add the chopped onion and minced garlic into the skillet. Sauté for about 3-4 minutes, or until the onion becomes translucent and fragrant.
Mix in the diced bell peppers, the entire can of diced tomatoes (juices included), cooked rice (or quinoa), kidney beans, salt, pepper, and Worcestershire sauce. Stir everything together until well combined and heated through.
Carefully transfer the beef mixture into the prepared casserole dish, spreading it in an even layer to ensure uniform cooking.
Next, sprinkle the shredded cheese evenly over the top of the beef mixture, making sure to cover all areas for that melty, cheesy goodness.
Cover the casserole with aluminum foil and place it into the preheated oven. Bake for 25 minutes to allow the flavors to meld.
After the initial baking, remove the foil and bake for an additional 10-15 minutes. Keep an eye out for the cheese to become bubbly and develop a golden-brown color.
Once baked to perfection, carefully remove the casserole from the oven and let it sit for about 5-10 minutes to set and cool slightly before serving.
Just before serving, garnish with freshly chopped parsley for a splash of color and an herbaceous note that complements the dish beautifully.
Notes
Serve directly from the casserole dish for a rustic feel, or portion onto plates and add a sprinkle of extra parsley for an elegant touch.