In a large stockpot, add the chicken, water (or stock), onion, celery, carrots, garlic, bay leaves, thyme, salt, and pepper.
Bring to a boil, then reduce heat to a simmer. Cover and cook for 45-60 minutes, until the chicken is tender.
Remove the chicken, let it cool slightly, then shred the meat (discard bones and skin).
Strain the broth and return it to the pot. Skim off excess fat if desired.
Add the shredded chicken back to the broth. Stir in butter for extra richness.
In a mixing bowl, whisk together flour, baking powder, and salt.
Cut in cold butter until the mixture resembles coarse crumbs.
Gradually add milk, stirring just until a soft dough forms (do not overmix).
On a floured surface, roll the dough to ¼-inch thickness, then cut into 2-inch squares or rectangles.
Bring the chicken stew to a gentle simmer.
Drop dumplings into the broth one at a time, spacing them slightly apart.
Cover and simmer for 15-20 minutes (do not stir too much—this makes them tough).
The dumplings should be fluffy and cooked through.
Ladle the stew and dumplings into bowls. Garnish with fresh parsley if desired.
