Cut bread into small squares, about 1/2". Spread on a large baking sheet. Let it sit on the counter overnight, or bake in 230° oven for 20-25 minutes or until dry.
Chop celery and onions. Mince garlic.
Heat up oil in a pan over medium heat.
Sauté garlic, onions, and celery until onions are translucent.
In a large bowl, add toasted bread, sautéd veggies, and seasoning. Toss until mixed.
Place in a 13"x 9" baking dish and spread evenly.
Pour vegetable stock over the bread.
Cover pan with aluminum foil.
Bake in the oven for 25 minutes. Afterward, take off foil and cook for another 10 minutes.