My recipe is pretty simple.

Buy a bag of bread chunks or unseasoned croutons. If you go with bread chunks, I usually leave the bag open overnight to harden a bit.
Saute diced onions and celery.
Mix bread chunks, onion, celery, pepper and salt to taste.
Add chicken broth (or veggie broth) until the mixture is soft.
Bake in the oven at 350 until hot.