Mix the cornbread mix according to box directions, except increase the eggs to 6.
Add the diced celery and onion to the cornbread batter.
Bake at temperature suggested on the box in an iron skillet, if possible, until cornbread is golden brown and done in the middle (check by sticking a sharp knife into the center) Cornbread may be baked 2-3 days before dressing is to be made.
Crumble cooled cornbread, and then add the remainder of the ingredients. Bake in a 350 degree oven until dressing is as done as YOU like it....about 30-45 minutes. Don't overcook or it will be dry.