In a large stockpot, heat olive oil over medium heat. Add beef and cook until no longer pink, breaking up with a wooden spoon; drain.
Add green pepper and onion and cook 5-7 minutes or until vegetables are softened. Add the remaining ingredients (tomato sauce through pepper) and bring to a boil.
Reduce heat, cover, and simmer for 40 minutes or until the rice is cooked. Top with shredded cheddar cheese, if desired.