- In a large stockpot, bring the chicken broth (preferably home-made) and Parmesan rind to a boil over medium-high heat.
- Add the tiny pastina noodles and cook until the pasta is tender for about 5 minutes, stirring occasionally.
- Add the chicken if using, and heat through about 3 minutes.
- Remove the Parmesan rind and discard.
- Stir in 1/2 of the cheese.
- Season with sea salt to taste.
- Ladle into soup bowls and sprinkle with the remaining cheese, if desired.
- Serve with warm, crusty Italian bread for sopping up any extra broth.