Sauté the celery and onion in the butter over medium heat until they turn translucent and caramelize. It pays to take your time with this step, because this is what really makes for a flavorful stuffing. Meanwhile, toast each piece of bread in a full loaf. I usually use a wheat bread, but you can use whatever your family likes best. Chop the toasted bread up into cubes. Add the celery and onion mixture and dried parsley. Salt and pepper the mixture well. Lightly beat the eggs with the milk, and pour over the top. Pour some of the chicken stock over the top, and start to mix everything together with a large spoon. Keep adding turkey stock until everything is moistened (wet but not soupy) - you may not need to use it all. Give your muffin pans a light misting of non-stick spray, and fill each cup with stuffing. Bake at 350°F for about 60 minutes. If you prefer a stuffing that's a little more moist, cover with aluminum foil for the first 45 minutes. This dish was created by Walmart Mom, Tara Kuczykowski.