Heat the butter (3 tablespoons) in a large pot over medium-high heat. Add the onions (1 large), green bell pepper (1), and garlic (1 tablespoon) and saute until softened, about 8-10 minutes. Add the ground beef (2 pounds), salt (1 ½ teaspoons), and pepper (½ teaspoon) and continue to cook, crumbling the beef with a spoon, until there is no longer any pink in the beef, about 5-6 minutes.
Add tomato sauce (2 cans), crushed tomatoes with their juices (1 can), water (3 cups), Worcestershire sauce (1 tablespoon), paprika (1 teaspoon), sugar (2 teaspoons), and dried Italian seasoning (1 tablespoon) and bring to a simmer. Reduce the heat to low, cover, and simmer for 20 minutes, stirring occasionally.
Add the pasta (2 cups), partially cover, and simmer until pasta is al dente, about 20-25 minutes. Sprinkle top with Mozzarella (16 ounces), cover, and cook on low for 2-3 minutes. Remove from the heat and allow to rest, covered for about 5-7 minutes. Sprinkle with parsley (2-3 tablespoons) if desired and serve.
