Chop the giblets and the meat that has been removed from the neck. Using a saucepot, bring the stock to a boil. Add the giblets, bouillon cubes, poultry seasoning, and raw stuffing to the mixture.
In a separate bowl, mix the cornstarch and water, and add to the boiling stock, stirring constantly. Reduce the heat and continue to cook for 2 to 3 minutes. Add the salt and pepper, to taste, and add the sliced boiled egg.