In a 5 quart pot, heat 2 tablespoons olive oil. Add onions and peppers and saute until soft, about 5 minutes. Add garlic and saute about 1 minute, or until fragrant.
Add Italian sausage and pepperoni and cook until sausage is no longer pink.
Add pasta, beef broth, tomato paste, pizza sauce, water and seasonings. Stir and bring to a boil.
Cover and simmer for 15 minutes or until pasta is tender, stirring at least once, .
Remove from heat and stir in mozzarella cheese, reserving 1/4 cup for sprinkling on the top. Replace the cover and let sit for five minutes. Garnish with diced green peppers and shredded Parmesan, if desired.