Preheat the oven to 375°F. Lightly oil a 9-inch by 13-inch baking dish and set aside until needed. Heat the vegan butter or olive oil in a large skillet over medium-high heat. When hot, add the onions and celery plus a pinch of salt, then cook until the vegetables are translucent and softened, approximately 10-12 minutes. Add the sage and crumbled vegan sausage, and cook for an additional 3-4 minutes, until the sausage is just beginning to brown. Transfer the mixture to a large bowl, then add the bread, parsley, and optional dried fruit. Season with salt and pepper, then pour in 3 cups vegetable broth, using a spatula or your hands to mix everything together until well-coated and moistened. If the mixture seems too dry, add some additional broth. Taste the stuffing, adjust seasonings as needed, then spread the mixture evenly in the prepared baking dish, pressing down with your hands to make it smooth and uniform. Cover with foil, place in the oven, and bake for 35 to 40 minutes, until heated through. Remove the foil and bake for an additional 10 minutes, until the top is lightly browned. Serve hot.