Combine the ground beef, ground pork, egg, breadcrumbs, Parmesan, minced garlic, parsley, salt, and pepper gently in a bowl. Shape the mixture into approximately 35–45 small meatballs, each about 3/4 to 1 inch in diameter.

For a lighter cooking method, arrange the meatballs on a parchment-lined baking sheet and bake at 400°F for 12–15 minutes, until cooked through. Alternatively, brown them in batches in a skillet with a little oil; they may finish cooking in the soup.

Heat the olive oil in a large soup pot over medium heat. Add the onion, carrots, and celery, then cook for 5–7 minutes until the vegetables begin to soften; add the garlic and cook for about 30 seconds.

Pour in the chicken broth and bring it to a gentle boil. Add the cooked or partially cooked meatballs, reduce the heat, and simmer for about 8–10 minutes.

Stir in the acini di pepe, orzo, or other very small pasta. Simmer according to the package directions, usually 7–10 minutes, stirring occasionally.

Add the chopped escarole and cook for 2–4 minutes, until tender. If using baby spinach instead, add it during the final 1–2 minutes.

Taste the soup and adjust the salt and pepper. Ladle it into bowls and serve hot with grated Parmesan and optional lemon wedges.