Step 1

To the bottom of a 6-quart or larger slow cooker, add the chicken breasts. Sprinkle with salt and pepper. Add the whole onion, carrots, celery, garlic, rosemary bundle, and bay leaf. Pour 6 cups of the chicken stock over the top. Cover and cook on LOW for 4 to 6 hours or HIGH for 2 to 3 hours, until the chicken is cooked through and reaches an internal temperature of 165 degrees F. The cooking time can vary greatly depending on your slow cooker model, so check the thickest part of the chicken for doneness early to ensure it does not overcook.

Step 2

Remove the chicken from slow cooker to a large mixing bowl or plate. Fish out and discard the whole onion, bay leaf, and rosemary springs (don’t worry if a few of the rosemary leaves are left in the soup). Shred the chicken—a hand mixer, two forks, or your fingers (if the chicken is cool enough) all work well for shredding. Set the shredded chicken aside.

Step 3

To cook the noodles on the stove (the best option so that you don’t worry about them over- or undercooking and so the noodles stay more intact): Towards the end of the soup’s cook time, cook the egg noodles until al dente according to package directions. Drain and add to the soup when the soup has finished cooking. Add back the shredded chicken. Stir and let cook on LOW for 5 minutes to absorb some of the flavor.

Step 4

To cook noodles directly in the slow cooker (the best option if you are willing to risk less-than-perfect noodles for the sake of not washing a separate pasta pot): Add the uncooked egg noodles to the soup. Cook on LOW for 10 minutes, or until al dente. Stir in the shredded chicken.

Step 5

Add as much of the remaining 1 cup chicken stock as you like to reach your desired consistency. (If you cooked your noodles in the slow cooker, you may also need to add some additional stock since the noodles absorb the stock as they cook). Serve hot with a sprinkle of fresh parsley.