Dice the onion into 1/2-inch pieces, slice the celery into 1/4-inch pieces, and slice the carrots into 1/4-inch rounds. Peel and mince the garlic fresh, strip the thyme leaves from their stems, and finely chop the rosemary. Cut the chicken breasts into 1-inch chunks for even cooking. I find that prep work done before the slow cooker starts cooking ensures nothing gets forgotten and the soup comes together seamlessly.

Transfer the prepared chicken, carrots, onions, celery, garlic, thyme, rosemary, and bay leaves to the slow cooker. Pour in the unsalted chicken stock and season with kosher salt and black pepper. Stir gently to combine, ensuring the chicken is submerged. Cover and cook on high for 3.5 hours (or on low for 5.5 hours) until the chicken reaches an internal temperature of 160°F. The long cooking time allows the vegetables to soften and the flavors to meld beautifully.

Carefully remove the chicken pieces from the slow cooker using a slotted spoon or tongs and transfer them to a cutting board. Let the chicken cool slightly (about 2-3 minutes), then shred it into bite-sized pieces using two forks. I like to shred the chicken while it's still warm because it pulls apart more easily and the texture is more tender.

Add the wide egg noodles directly to the slow cooker with the hot broth and vegetables. Stir well to separate the noodles and ensure they're submerged. Cover and cook on high for 25-30 minutes, stirring occasionally to prevent sticking, until the noodles are tender. The noodles will absorb some of the broth while cooking, so the soup will thicken slightly.

Return the shredded chicken from Step 3 to the slow cooker and stir gently to combine with the pasta and vegetables. Cover and cook on high for 5 minutes until the chicken is heated through and fully incorporated.

Taste the soup and season with additional salt and black pepper as needed. Ladle the soup into bowls and finish each serving with a generous sprinkle of fresh chopped parsley. The bright parsley adds both color and a fresh herbal note that contrasts beautifully with the warm, savory broth.