Heat the oil over medium heat in a large stock pot. Add the beef, using a wooden spoon to break it up; brown for about 5 minutes. Add the onions and mushrooms, with a good pinch of salt and pepper. Cook until the beef is completely browned and the vegetables are softened, 7-8 minutes. Stir in the garlic, spices and flour.
Add the tomato sauce, stewed tomatoes, spinach and water. Bring to a boil, then cover, reduce to medium low and simmer for 30 minutes, until the flavors have developed. Taste and adjust seasoning as you like.
Add the pasta and simmer uncovered, until the pasta is cooked al dente. Serve garnished with the mozzarella.
Note: This soup is fantastic leftover. Since the pasta will absorb moisture which will thicken the soup, you may need to add more water the following day when you reheat it, to return it to a "soupy" consistency.
Yields about 6 servings
Recipe from Curly Girl Kitchen