In a mixing bowl, combine ground beef, bread crumbs, egg, garlic powder, Italian seasoning, salt, and pepper. Mix until well combined.

Form the mixture into small meatballs, about 1 inch in diameter.

In a large pot, heat olive oil over medium heat. Add meatballs and cook until browned on all sides, about 5-7 minutes. Remove meatballs and set aside.

In the same pot, add diced onion and minced garlic. Sauté until onion is translucent, about 3-4 minutes.

Pour in chicken broth and diced tomatoes. Bring to a simmer.

Return meatballs to the pot and simmer for 10 minutes.

Stir in heavy cream, spinach, Italian seasoning, salt, and pepper. Cook for an additional 5 minutes until heated through.

Ladle the soup into bowls and serve hot, garnished with fresh herbs if desired.