Place the whole chicken and carrots, celery, onion, garlic cloves, bay leaves, whole peppercorns, fresh parsley stems, dried thyme, and cold water in a very large pot. Bring to a boil over high heat, then skim foam and reduce to a steady simmer.

Simmer for 1.5 hours, keeping the broth gently bubbling until the chicken is very tender. The surface should stay calm with occasional bubbles around the edges.

Strain the broth into a clean pot, discarding the used vegetables. Remove all meat from the chicken and shred it into bite-size pieces.

Return the clear broth to the pot and taste, then season with salt. Stop and adjust until the broth has balanced flavor.

Bring the seasoned broth to a simmer, then add sliced carrots, sliced celery, and diced onion. The vegetables should begin softening immediately.

Cook for 10 minutes, until the vegetables are tender. You should see carrots slightly softened and onion turning translucent.

Add the wide egg noodles and cook for 10 minutes until they start to soften. Look for noodles to expand and become pliable.

Add the shredded chicken and fresh parsley, then cook for an additional 6–8 minutes. The noodles should be tender and the chicken should be heated through.

Adjust the final seasoning with salt and pepper to taste. The broth should taste cohesive with no bland edges.