shredded mozzarella, ricotta cheese, parmesan cheese and basilfor garnish
In a large saucepan, saute ground beef in olive oil until cooked through. Add onion, carrot, garlic, and spinach and saute for 5 minutes. Add another drizzle of olive oil if necessary.
Add marinara sauce, beef broth, tomato sauce, Italian seasoning, and bay leaf. Simmer, partially covered, stirring occasionally for 20 minutes.
Bring mixture to a boil, add pasta, and cook uncovered until pasta is tender, about 10 minutes. Stir frequently so that the pasta doesn't stick to the bottom of the pan. Add water as needed (I added 2 cups), as the pasta will absorb some of the liquid. Discard the bay leaf, add salt to taste (this will depend on how much salt was in your broth and marinara sauce).
Top each bowl of soup with mozzarella, ricotta, and parmesan cheese. Garnish with basil, if desired. See note regarding the soup thickening.
The pasta will continue to absorb liquid as it sits. If you are not eating it all immediately, you will need to add additional water or beef broth to make it "soupy" again.