From the ArcaMax Publishing, Recipes Newsletter:
http://www.arcamax.com/news/recipes/s-127735-872568
Take one loaf of stale challah. Cut in one inch cubes. Toast the
cubes for approximately 5 minutes in the oven. Allow to cool.
Chop celery, mushrooms and whatever vegetables you want to include.
Mix with the toasted bread cubes. Put in ~10"x14" greased pan. Pour
2-3 cups (more if needed) chicken/vegetable broth over.
Cover with foil. Bake for 30-45 minutes.