In the melted fat, cook the celery, parsley, and onion over low heat, until onion is soft but not browned.
In the meantime, mix the dry seasonings with the bread cubes. Add vegetables to bread and blend.
Pour the liquid gradually over the surface, stirring lightly. The exact amount added will depend on whether you want a dryish or moist-light dressing. Two well beaten eggs, added along with the other liquids, help to make a light dressing. Add more seasoning if desired.
Pack lightly into the body cavity of the bird just before placing it in the oven.
Any excess dressing that doesn't fit into the bird can be placed in a covered casserole dish and baked at 350 degrees for 35 minutes. Remove cover and bake another 10 to 15 minutes until the top is browned and crispy.