Melt butter/ghee in a large skillet over medium heat. Add diced onions and celery, and onion powder & poultry seasoning; season with salt and pepper and cook 5 minutes. Add 3 cups chicken broth and bring to a simmer. Whisk eggs in a large bowl; add all bread crumbs, then slowly pour in the vegetable/broth mixture and toss. Mixture should be wet enough to stick to the spoon and would easily form into balls; add more broth if necessary. Transfer to a buttered (or oiled) 3-quart baking dish. Cover and bake 10-15 minutes, then uncover and bake until golden, 10-15 more minutes.