Heat the olive oil in a large pot and brown the meatballs just until they get some color — they don’t need to cook all the way through. Remove and set aside.

Add the onion, carrots, and celery to the pot and cook for 5 minutes until softened. Pour in the chicken broth and add the Parmesan rind if using. Bring to a simmer, then add the pasta and return the meatballs to the pot. Cook until the pasta is tender and the meatballs are fully cooked, about 10–12 minutes.

Stir in the spinach and let it wilt for a minute. Taste and season with salt and pepper. Ladle into bowls and top with extra Parmesan.

If you want this thicker, let it simmer a little longer. If it gets too thick after sitting, just splash in more broth when reheating. This one reheats beautifully and tastes even better the next day.