In a large pot, add the chicken broth, halved chicken breasts, celery pieces, and onion chunks. Bring it to a boil. Once boiling, reduce the heat to low, cover partially, and simmer for about 20 minutes or until the chicken is cooked.
While the chicken is cooking, prepare the dumplings. In a mixing bowl, whisk together the flour, baking powder, and salt. Slowly add the milk until a dough forms.
On a floured surface, roll out the dough until it’s about 1/4 inch thick. Cut the dough into rectangular pieces, about 1 to 2 inches in size.
Once the chicken is cooked, remove it from the pot and shred it. Discard the onion and celery.
Drop the dough pieces into the simmering broth. Stir occasionally and cook for 20-30 minutes until the dumplings are cooked through and the broth thickens.
Add the shredded chicken back into the pot, stirring to combine. Season with salt and pepper to taste. Serve warm and enjoy!