Simmer the Chicken: Place chicken thighs, stock, bay leaves, onion, celery, carrots (if using), garlic, and thyme into a large Dutch oven or stockpot. Bring to a gentle boil, then reduce heat and simmer uncovered for about 40 minutes, skimming off foam as needed.
Remove and Shred: Take the chicken out of the pot and let it cool slightly. Discard the skin and bones, shred the meat, and set aside.
Make the Dumplings: In a medium bowl, whisk together flour, baking powder, and salt. Stir in buttermilk and melted butter (or reserved chicken fat) until a soft dough forms. Do not overmix.
Drop the Dumplings: Reduce the broth to a low simmer. Using a spoon, drop rounded portions of dough gently onto the surface. Cover and cook undisturbed for 15 minutes. No peeking: steam is the magic here!
Return the Chicken: Stir shredded chicken back into the pot and let everything mingle for another 5 minutes.
Skim: Skim off a few spoonfuls of golden chicken fat before adding the dumplings and stir it back in at the end. It’s an old Southern trick that makes the broth silky and irresistible.
Finish and Serve: Taste and adjust seasoning. Garnish with fresh parsley and serve steaming hot.