Mix breadcrumbs, parmesan cheese, nutmeg, half the minced onion, egg, ground beef, and ground pork in a bowl.

Shape this mixture into small meatballs about 3/4 inch in diameter.

In a large pot, heat 3 tablespoons of olive oil over medium-high heat.

Add meatballs and cook until browned all over, then remove from the pot and set aside.

In the same pot, add remaining olive oil, garlic, and onion.

Cook until the onion is soft and translucent, then add flour and stir constantly for one minute.

Pour in the white wine and chicken broth.

Add pasta, bring the mixture to a simmer, and cook until the pasta is tender.

Add spinach and meatballs back to the pot.

Simmer until the spinach is wilted and meatballs are thoroughly cooked.