Rinse the chicken and put in a large stockpot. Cover with water and bring to a boil. Skim off any scum that rises, then add the bay leaves, salt, pepper, garlic powder, carrots, celery and onion. Simmer 45 minutes to an hour then remove the chicken and let cool a bit so you can remove the meat. Discard the bones and skin and fat. Shred the chicken into large pieces and return to the pot of broth.
Combine the flour and water, then stir into the broth to thicken.
Mix up the dumplings by sifting together the flour, baking powder, salt and pepper. (And next time I'll add some dried parsley and cayenne pepper.) Cut in the butter then add the milk and mix. I did this all the food processor.
Bring the broth to a simmer and slowly drop in small spoonfuls of the dumpling mix. Simmer 15 minutes until cooked through. Try not to stir too much as you don't want the dumplings to break up into small bits.