Add your chicken carcass to a large dutch oven or soup pot and add enough water to cover or almost cover (almost 5 quarts for my pot)
Add in half of the onion, half of the celery, garlic, bay leaf, and the bundle of thyme.
Bring soup to a boil and reduce to a simmer. Cover and simmer for two to three hours. Taste for seasoning and add more salt if needed.
Remove chicken from the broth with a slotted spoon or spider strainer. Pick chicken from the bones and return the chicken to the broth.
Add the remaining onion and celery, carrots and chopped thyme.
Return to a boil.
In a medium bowl, mix together the flour, baking powder, salt and enough dry milk mix to make 1 c of milk (if using real milk skip this step). Cut in the butter. Gently stir in water or milk (if not using dry milk mix). Stir just until combined, don’t over mix.
Using 2 spoons drop the dumpling mix onto the boiling soup (carefully!) Use one spoon to scoop and the other spoon to scrape it off into the pot.
Reduce to a simmer and simmer uncovered for 10 minutes.
Cover and continue simmering for another 10 minutes.
Uncover and serve. Just be sure to let it cool a bit before digging in.
Refrigerate leftovers or portion them into single servings and freeze them.