Note that vegetable trimmings are the otherwise unused ends of celery, carrot and onion that Chef Hacker collects and freezes when cutting those vegetables for various dishes. They are great to flavor broth and stock such as this. They can also be stuffed inside the breast cavity of chicken or turkey roasts where they add complexity of flavor and help the roast retain moisture. Just be sure to remove and discard the trimmings prior to serving the dish.