Prep: Preheat oven to 350°F with the rack in the middle. Grease a 9x13" baking dish, or a 3 quart casserole dish, with vegan butter or olive oil.
Brown the sausage: Preheat a nonstick skillet over medium-high heat. Add in the vegan sausage and break it up into crumbles with your spoon. Pan-fry until nicely browned. (I actually like to overcook the sausage a little to keep it from getting mushy in the texture.) Remove the sausage to a plate.
Sauté aromatics: In the same pan, melt 1/2 cup vegan butter over medium heat. Add in the diced onion, celery, and minced garlic and sauté for 8-10 minutes. We want the veggies to be soft and buttery, not browned. During the last 2 minutes, stir in the minced fresh sage, thyme, rosemary, 1/4 cup chopped parsley, and black pepper. Season with salt.
Add the broth/bouillon: Pour in the veggie broth, starting with only 2 cups. If using bouillon cube or paste, you can dissolve it with 2 cups water directly in the pan.
Add the bread: Transfer the aromatics and broth mixture to a large mixing bowl, then add in the dried bread pieces and give everything a thorough toss. Drizzle in some of that extra reserved broth if needed until the bread feels evenly moistened but not soggy. Artisan-style breads will be very thirsty, whereas softer white breads will require much less liquid. We don't want loose broth at the bottom of the bowl.
Transfer and bake: Once all the bread has been moistened, mix in the browned vegan sausage. You can give the stuffing a taste and add more salt and pepper if you like. Transfer the stuffing into the greased baking dish, cover tightly with aluminum foil, and bake in preheated oven for 30 minutes.
Crisp the top: Remove the foil and continue baking for about 10-15 minutes to crisp up the top. If you like an extra crispy topping, you can increase the heat to 375°F for this step.
Serve: Remove from oven and allow to cool for about 5 minutes. Sprinkle with fresh chopped parsley if desired, and serve.