To make the meatballs, add the beef and pork to a large mixing bowl. Add in bread crumbs, parsley, oregano, parmesan, egg, salt and pepper. Gently toss and break up mixture with hands to evenly coat and distribute. Shape mixture into very small meatballs, about 3/4 inch to 1 inch and transfer to a large plate.

Heat 1 tablespoon olive oil in a large non-stick pan over medium-high heat. Add half of the meatballs and cook until browned, turning occasionally (to brown on 2 or 3 sides), about 4 minutes total. Transfer meatballs to a plate lined with paper towels while leaving oil in skillet. Repeat process with remaining meatballs (meatballs will not be fully cooked through at this point, but they'll continue to cook through in the soup).

While meatballs are browning, heat 1 tablespoon olive oil in a large pot over medium-high heat. Add carrots, onions and celery and saute until vegetables are soft, about 6 - 8 minutes. Add garlic and saute 1 minute longer. Pour in chicken broth, season soup with salt and pepper to taste and bring mixture to a boil. Add in pasta and meatballs, reduce heat to medium. Cover and cook, stirring occasionally until pasta is tender and meatballs have cooked through, about 10 minutes. Add spinach during the last minute of cooking time. Plate and sprinkle each serving with parmesan cheese.