Preheat your oven to 375°F and grease a baking dish with butter. Spread the shredded chicken evenly in the dish. Sprinkle chopped celery over the chicken for added texture and flavor.
In a mixing bowl, whisk together the flour, baking powder, salt, and garlic powder. Slowly add the melted butter and milk, stirring until a thick batter forms. This will create the soft dumplings when baked.
Carefully pour the dumpling batter over the chicken layer, spreading it evenly. Do not stir—this layering technique helps achieve the best texture.
Gently pour the warm chicken broth over the batter. Again, do not mix—this step allows the flavors to blend while baking.