Heat a Dutch oven over medium heat; add ground beef and onion. Cook and stir until beef is no longer pink, 5-7 minutes. Drain. Add garlic; cook 1 minute longer. Add diced tomatoes, tomato sauce, water, broth, pasta and seasonings. Stir; bring to a boil. Cover, reduce heat and simmer until pasta is tender, stirring occasionally. Top with spinach; cover just until wilted. Stir. If desired, sprinkle with Parmesan cheese.