In a large mixing bowl, combine ground beef, ground pork, breadcrumbs, Parmesan cheese, parsley, egg, garlic, oregano, salt, and pepper. Mix until well combined.
Roll the mixture into small meatballs, about 1 inch in diameter.
If desired, place the meatballs on a baking sheet and bake at 400°F (200°C) for 15 minutes, or you can brown them directly in the pot.
In a large pot or Dutch oven, heat olive oil over medium heat. Add diced onion, carrots, and celery. Sauté for about 5-7 minutes until the vegetables are tender.
Pour in the chicken broth and diced tomatoes, followed by dried basil and, if desired, red pepper flakes. Bring the mixture to a gentle boil.
Carefully add the meatballs to the soup. Reduce heat to low and let the soup simmer for 15 minutes, ensuring the meatballs are cooked through.
Stir in the small pasta and cook for an additional 10 minutes, or until the pasta is tender.
Taste and adjust seasoning if necessary. Serve hot, garnished with fresh basil leaves if desired.