Place a large soup pot over medium-high heat. Add the diced tomatoes with their juices, beef broth, water, and Italian seasoning. Stir everything together until evenly combined.
Bring the broth mixture to a boil, allowing the tomatoes and seasonings to blend into the liquid.
Add the frozen cooked Italian-style meatballs, frozen Italian-blend vegetables, and dried star-shaped pasta. Stir gently to distribute the ingredients throughout the soup.
Bring the soup back to a boil, then reduce the heat to medium-low.
Cook for approximately 10 minutes, stirring occasionally, until the pasta is tender, the vegetables are heated through, and the meatballs are thoroughly hot.
Check that the meatballs are heated through to a safe internal temperature of 165°F (74°C). If the pasta or meatballs need more time, continue simmering until ready.
Ladle the hot soup into individual serving bowls.
Sprinkle the grated Parmesan cheese over each serving and enjoy warm.