Dice the onion and bell peppers, mince the garlic, and rinse the rice if desired. Set the prepared vegetables and rice near the stove so they can be added without delay.

Heat a large Dutch oven or soup pot over medium-high heat. Add the ground beef and diced onion, then cook for 6–8 minutes, breaking the beef into small pieces, until browned and the onion has softened; drain excess fat if necessary.

Add the minced garlic and diced bell peppers to the browned beef. Cook for 2–3 minutes, stirring frequently, until the garlic smells fragrant and the peppers begin to soften.

Stir in the diced tomatoes with their juices, tomato sauce, beef broth, Italian seasoning, kosher salt, black pepper, and Worcestershire sauce if using. Scrape the bottom of the pot as you stir to release any flavorful browned bits.

Bring the mixture to a boil, then reduce the heat to low. Cover the pot and simmer for about 15 minutes so the tomato broth and seasoned beef can come together.

Stir in the uncooked long-grain white rice. Cover again and simmer for another 15–20 minutes, stirring occasionally to prevent the rice from sticking, until the grains are tender.

Taste the soup and adjust the salt and black pepper as needed. If the rice has absorbed more liquid than expected, add additional broth or water until the soup reaches your preferred consistency.

Ladle the soup into bowls while it is hot. Top with shredded mozzarella or Parmesan and chopped fresh parsley, if desired, and serve immediately.