Saute the onion, garlic, and celery in a large pot with butter. Cook that for a few minutes and then, add bread cubes, seasonings, and chicken stock. Mix together.
Grease a baking dish with butter and pour out the stuffing into the dish. Top with some Gluten-Free Panko and a few pieces of butter.
Bake at 350 degrees for 35-40 minutes, until top is golden brown and crispy. Serve right away while nice and hot.