Boil Potatoes (just like if you were going to make mashed potatoes). When soft and tender, drain and place in bowl. Mash with fork adding 4 tablespoons of butter. Mash potatoes with milk until they are a thick, but creamy texture. Do not over whip the potatoes – you want a thicker consistency. Add salt and pepper to taste.
While the potatoes are cooking, in a large pan saute onions, celery and parsley in the remaining butter for about 4-6 minutes, until tender. Reduce heat and add in bread. Keep in pan for about 4-5 minutes and stir frequently to keep bread from sticking to pan.
Fold bread mixture and chicken stock into mashed potatoes. Fold 3 eggs into the mixture. Stir completely together.
Put into a greased 11x17 baking pan and cook for 45 minutes.