In a large pot, combine 6 cups of low-sodium chicken broth, 1 chopped sweet onion, 2 peeled and coarsely chopped carrots, and 2 coarsely chopped celery stalks. Add 3 smashed garlic cloves and sprinkle in some kosher salt. Place the pot over high heat and bring the mixture to a boil.

Once boiling, reduce the heat to medium-low and let it cook for about 10 minutes, until the vegetables are tender.

Transfer the softened vegetables and about 1 cup of the broth into a blender. Blend until smooth and creamy. Return it to the pot and stir.

Add 2-3 thyme sprigs, 1-2 fresh bay leaves, and the Parmigiano rind to the blended broth. Let it simmer for an additional 5 minutes.

Bring your soup back to a boil over medium heat. Stir in 1 cup of uncooked pastina pasta, and let it simmer for 18-20 minutes until the pasta is tender.

With 3 minutes remaining, stir in 2 cups of shredded rotisserie chicken and remove the thyme sprigs, bay leaves, and Parmigiano rind before serving.

Ladle the soup into warm bowls, garnish with fresh parsley and a sprinkle of grated Parmigiano-Reggiano, and serve hot with crusty bread.