Sweet butternut squash, homemade turkey stock, and three types of fresh herbs -- sage, thyme, and rosemary -- give this stuffing deep flavor.
Preheat oven to 425 degrees. Toss squash with oil and sage; season with salt and pepper. Spread in a single layer on a rimmed baking sheet. Roast, flipping once, until golden brown and tender, about 40 minutes. Crumble sage.
Melt butter in a large straight-sided skillet over high. Add onions, celery, thyme, rosemary, chestnuts, 2 teaspoons salt, and 3/4 teaspoon pepper. Cook, stirring occasionally, until onions are translucent, 5 to 6 minutes. Add to a large bowl with bread and squash mixture. Drizzle with stock; toss to combine. Stir in parsley; season with salt and pepper. Let cool completely before stuffing bird.
Leave the bread out overnight, or dry it in a 350-degree oven for about 10 minutes.