Heat oil in a 6-qt. saucepan over medium-high. Add celery, carrot, onion, and rosemary and cook until soft, 8¨C10 minutes. Add stock and chickpeas and simmer for 5 minutes. Remove half of chickpeas and pur¨¦e 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.