Creating Italian Meatball Soup is a straightforward process. Follow these steps for a delightful outcome:

1. Prepare the Meatballs: In a large bowl, combine the ground beef, breadcrumbs, grated Parmesan, egg, minced garlic, oregano, salt, and black pepper. Mix until just combined.
2. Form Meatballs: Shape the mixture into meatballs, about 1 inch in diameter. Place them on a plate and set aside.
3. Sauté Vegetables: In a large pot, heat the olive oil over medium heat. Add the diced onion, carrots, and celery. Sauté until the vegetables are tender, about 5-7 minutes.
4. Add Broth and Tomatoes: Pour in the chicken or vegetable broth and add the diced tomatoes (with juice). Stir well to combine.
5. Add Meatballs: Gently add the meatballs to the pot, ensuring they are submerged in the broth.
6. Simmer: Bring the soup to a gentle boil, then reduce the heat. Cover and let it simmer for about 25-30 minutes, or until the meatballs are cooked through.
7. Add Spinach: Stir in the spinach and cook for an additional 5 minutes, just until wilted.
8. Taste and Adjust: Taste the soup and adjust seasoning if necessary (add more salt or pepper to taste).
9. Serve: Ladle the soup into bowls and garnish with fresh parsley and extra Parmesan cheese, if desired.

These simple steps will guide you in creating this incredible soup that will fill your kitchen with lovely aromas.