In a large glass bowl, microwave butter, celery, and onion on high power for 4-5 minutes, stirring several times, OR melt butter in a skillet on medium heat and cook onion and celery, until softened. Combine the cooked mixture with the remainder of the ingredients in a large mixing bowl. Mix well. To stuff poultry, dot cavity with an additional 2 tsp (10 mL) butter, sprinkle with a dash of salt and pepper and loosely stuff immediately before roasting poultry. Variation: To make individual servings, cook in greased muffin tins, covered with tin foil for 15 minutes. Uncover for 5 additional minutes of cooking. Yield: 8 muffin tins, or 6 cups (1.5L).