Preheat oven to 350 degrees F.
In a large saucepan heat butter until melted.
Add the onions and celery and saute over medium heat for 6-8 minutes or until softened.
Add the chicken stock and bring mixture to a boil.
Turn off the heat, add the croutons or bread and fluff with a fork gently (make sure not to over-stir the mixture or it will become mushy).
Transfer to a baking dish and bake for 30 minutes or until top is golden brown.
