Heat 2 tablespoons of olive oil in a large pot over medium heat.
Add the diced onions and cook for 3-4 minutes until they start to soften.
Stir in the minced garlic and cook for an additional minute until fragrant.
Add the ground beef or turkey to the pot, using a wooden spoon to break it apart. Cook until browned, about 5-7 minutes.
Stir in the chopped bell peppers and cook for another 3-4 minutes until they begin to soften.
Add the diced tomatoes (with juices), beef or vegetable broth, cooked rice, tomato paste, oregano, basil, salt, and pepper to the pot.
Bring the mixture to a simmer, then reduce the heat to low. Cover and let it cook for 20 minutes, stirring occasionally.
Adjust seasoning with additional salt and pepper if needed.
Serve hot, garnished with shredded cheddar cheese and fresh parsley if desired.