1. Heat olive oil in a large pot over medium heat. Add onion and garlic, and sauté 5 minutes or until softened. Add tomato, and cook 1 minute. Stir in broth and rosemary, and bring to a boil; reduce heat, and simmer, covered, 5 minutes. Add pasta, stirring to blend, and simmer 5 to 6 minutes more.
2. Add spinach, salt, and pepper. Simmer, stirring often, 3 minutes or until spinach is wilted and pasta is just tender. Ladle soup into bowls, and sprinkle with cheese or stir in a spoonful of pesto.