Preparation Preheat oven to 375°F. Butter 4-cup casserole. Cook potato in small pot of boiling salted water until just tender, about 5 minutes. Drain and set aside. Heat oil in heavy medium skillet over medium heat. Add onion, apple and celery and sauté until onion is translucent, abut 5 minutes. Add potato and sauté 1 minute. Add stuffing mix, sage and broth. Cover skillet, reduce heat to medium-low and cook until stock is absorbed, about 10 minutes. Season to taste with salt and pepper. Transfer dressing to prepared dish. (Can be prepared 2 hours ahead. Let stand at room temperature.) Cover with foil and bake until heated through, about 30 minutes. Uncover and bake until top begins to brown, about 15 minutes.
Preparation Preheat oven to 375°F. Butter 4-cup casserole. Cook potato in small pot of boiling salted water until just tender, about 5 minutes. Drain and set aside. Heat oil in heavy medium skillet over medium heat. Add onion, apple and celery and sauté until onion is translucent, abut 5 minutes. Add potato and sauté 1 minute. Add stuffing mix, sage and broth. Cover skillet, reduce heat to medium-low and cook until stock is absorbed, about 10 minutes. Season to taste with salt and pepper. Transfer dressing to prepared dish. (Can be prepared 2 hours ahead. Let stand at room temperature.) Cover with foil and bake until heated through, about 30 minutes. Uncover and bake until top begins to brown, about 15 minutes.