In a large pot, heat the olive oil over low heat and sauté the onion, celery, and garlic for 4 to 5 minutes until veggies begin to soften. Add the vegetable stock, Herbes de Provence, garlic powder, sage, salt, and bread. Mix well until the vegetable stock has absorbed into the bread.
Transfer to a 13x9 baking dish and top with crushed walnuts. Bake uncovered in a 350 degree oven for 30 minutes until brown and crispy.
Sourdough Bread: You can use homemade sourdough bread, or a store-bought loaf. Either way you will have delicious stuffing. Sourdough bread typically has less sodium that normal bread, so even buying store bought can be OK for those cutting back on their sodium intake (but check the labels to make sure the sodium content fits in with your dietary needs). I have a simple guide to homemade sourdough in 1 week, check it out!
If you are gluten free, make sure you choose a gluten free sourdough loaf to cube up for this recipe.