In a microwave-safe medium bowl. add the diced bell peppers and onions. Cook for 6 minutes in the microwave, until softened. Set aside.
In a large, nonstick pan or pot, add ground beef and cook, breaking up the meat and stirring occasionally, until no longer pink, about 3 minutes. Drain in sink and set cooked meat aside.
In the same large pan or pot, heat oil over medium heat. Add cauliflower rice and sauté until softened, about 6 minutes. Stir often.
To the cauliflower rice, add cooked bell peppers/onions and all the seasonings. Mix well. Stir in browned beef, broth, tomatoes, tomato sauce, and Worcestershire sauce. Bring up to a boil, then down to simmer. Cover and continue to simmer for about 20-25 minutes until all veggies are soft.
Ladle 2 cups of soup into each bowl and top each with 2 tablespoons shredded cheese, if desired.
Any leftovers freeze great!