Using cheese-filled tortellini as the noodle here adds more flavor than plain pasta; a hint of miso further enriches the broth. You can make the soup a couple of days ahead--just leave out the pasta, as it will swell once it goes into the liquid. Reheat the soup until it comes to a simmer. Then add the tortellini, and cook 6 minutes.
Serves 6 (serving size: about 1 1/3 cups)
Heat oil in a Dutch oven over medium-high. Add onion, carrot, and celery; sauté 8 minutes. Add stock, water, miso, pepper, and salt; increase heat to high. Bring to a boil. Cover and reduce heat to medium-low; simmer 5 minutes. Stir in tortellini. Cover and reduce heat to medium; cook 6 minutes. Stir in chicken and parsley.