Heat oil in a 6-qt. saucepan over medium-high. Add celery, carrot, onion, and rosemary and cook until soft, 8–10 minutes. Add stock and chickpeas and simmer for 5 minutes. Remove half of chickpeas and purée until smooth; return chickpeas to pan. Add pasta and cook until al dente, 10 minutes. Season with salt and pepper. Serve with parsley and Parmigiano sprinkled on top.
From Saveur: Italian Comfort Food by The Editors of Saveur, Weldon Owen 2015.