Ingreadient

• 4 tablespoons unsalted butter
• 1 medium carrot, finely chopped
• 1 celery rib, finely chopped
• 1/2 medium onion, finely chopped
• 2 cups cooked chestnuts (from one [14.8-ounce] vacuum-packed jar)
• 1 cup ruby port
• 1 thyme sprig
• 3 cups chicken stock or lower-sodium broth
• 1/2 cup heavy cream
• salt
• freshly ground black pepper