Earla's Old Time Potato Stuffing

Earla's Old Time Potato Dressing (may also be eaten as we did in my childhood, as a stuffing). Ready in one hour.  Serves six or more.  From allrecipes.com by Lauren Buckner with a few changes by moi. My mom made this.

Ingredients:
1 large onion, chopped fine
3/4 cup finely chopped celery
1/4 cup (or more) butter
1/4 turkey or chicken broth (or veggie broth)

8 slices day old white bread, cubed with crusts removed
3 cups mashed potatoes (you can cheat and use prepared dry potato flakes to make 3 cups)
1 egg, beaten
1 1/2 t. poultry seasoning  (I'll used fresh thyme, summer savory, and the herbs that constitute poultry stuffing).
1 t. kosher salt

1/2 t. freshly ground black pepper
1/4 t. ground nutmeg (I always do fresh)

Directions:

1. In a skillet, saute onion and celery in butter until tender.  Remove from the heat; stir in broth.  In a large bowl, combine bread cubes, prepared potatoes, egg and all seasonings.  Sir in onion mixture.  If mixture seems dry, add more melted butter or broth. Transfer to a greased  2-qt. baking dish.  Cover and bake at 325 degrees F. for  40 minutes.  Uncover and bake for another 15-20 minutes until the top is browned and a  meat thermometer reads 160 degrees.  You can also put a little extra butter, salt and pepper on top and place under a broiler until browned and bubbly.