In a bowl, combine the ground beef, ground pork, egg, breadcrumbs, Parmesan cheese, minced garlic, parsley, salt, and pepper. Mix until well combined. Form the mixture into 1-inch meatballs and set aside.
In a large pot or Dutch oven, heat 1 tbsp of olive oil over medium heat. Add the meatballs and cook until they are browned on all sides and cooked through, about 7-10 minutes. Remove the meatballs from the pot and set aside.
In the same pot, add the remaining tablespoon of olive oil, chopped onions, carrots, and celery. Sauté the vegetables until they start to soften, about 5 minutes.
Pour in the chicken broth and white wine and bring to a boil. Add the acini di pepe pasta, and simmer until the pasta is al dente, about 10 minutes.
Return the meatballs to the pot and continue to simmer for an additional 5 minutes.
Stir in the fresh spinach and cook until the spinach is just wilted, about 1-2 minutes. Taste and season with salt and pepper as needed.
To serve, ladle the soup into bowls and sprinkle with extra grated Parmesan cheese.