Prepare the Meatball Mixture: In a large mixing bowl, combine the ground beef, Italian bread crumbs, grated Parmesan, chopped parsley, egg, minced garlic, dried oregano, salt, and black pepper. Mix gently until just combined.

Shape the Meatballs: With clean hands, shape the mixture into 1-inch meatballs, placing them on a lined baking sheet. You should get about 20 meatballs.

Sauté the Vegetables: In a large pot over medium heat, add olive oil and sauté chopped onion, carrots, and celery for about 5 minutes until soft and fragrant.

Brown the Meatballs: Add the meatballs to the pot in a single layer, browning them for about 3–4 minutes, turning occasionally.

Add the Broth and Tomatoes: Pour in the chicken broth and add the diced tomatoes. Stir gently and bring to a gentle simmer.

Simmer the Soup: Reduce heat to low, allowing the soup to simmer for 15–20 minutes until the meatballs are cooked through.

Stir in Pasta and Spinach: Stir in the cooked pasta and fresh spinach, heating for an additional 3–5 minutes until the spinach wilts.

Adjust Seasoning and Serve: Taste and adjust seasoning if needed, then ladle into bowls and garnish with Parmesan and basil.