In a frying pan, sauté the onion in the butter for 10-12 minutes, or until the onion is tender.
Place the bread cubes in a large bowl. Pour the butter and onion mixture over the bread cubes and mix. Add the seasonings, chicken stock, eggs and all but 1/3 cup cheddar cheese (set this aside for topping).
Spray a 2-quart casserole dish with cooking spray. Put the stuffing in the prepared pan.
Sprinkle the remaining cheddar cheese on top of the stuffing.
Bake at 350 degrees for 30 minutes or until golden brown.
Sprinkle the top with fresh parsley before serving.