Ingredients

1 (1-pound) loaf rustic white bread, crusts removed, and cut into 1-inch cubes

1 small butternut squash, peeled, seeded, and cut into 1/2-inch pieces

6 tablespoons olive oil

Coarse salt and freshly ground pepper

1/2 cup thinly sliced shallots

2 ribs celery, chopped

1 small leek, white part only, chopped

4 cups cleaned, dried, stemmed, and torn mustard greens

12 ounces cremini mushrooms, trimmed and quartered

1 tablespoon chopped fresh sage

3 tablespoons fresh flat-leaf parsley, chopped

2 teaspoons fresh thyme

2 1/4 cups low-sodium store-bought chicken broth

1/4 cup (1/2 stick) unsalted butter, plus more for baking dish, if using

Preparation

Arrange bread in a single layer on a baking sheet, and let stand, uncovered, at room temperature overnight. (Alternatively, bake bread in a 250-degree oven until dry but not browned, 25 to 30 minutes.)

Transfer bread to a large bowl. Preheat oven to 400 degrees.

In a medium bowl, toss squash with 2 tablespoons olive oil until coated; season with salt and pepper. Arrange squash in an even layer on a baking sheet; transfer to oven and roast until squash is tender, about 15 minutes. Transfer squash to bowl with bread cubes.

Heat 2 tablespoons oil in a large skillet over medium-low heat. Add shallots, celery, and leek. Cook, stirring occasionally, until vegetables are soft, about 5 minutes. Fold in mustard greens and cook until just wilted, about 1 minute. Transfer to bowl with bread and squash.

Heat remaining 2 tablespoons oil in skillet over medium heat. Add mushrooms and cook, stirring occasionally, until softened, 2 to 3 minutes. Transfer to bowl with bread and vegetables.

Heat chicken broth in a small saucepan with butter and over medium-low heat until butter is melted; pour over bread mixture. Add sage, parsley, and thyme to bread mixture; season with salt and pepper; mix until well combined. Let stuffing mixture cool completely if stuffing in turkey.

To cook stuffing in a turkey: Loosely stuff into a turkey, and roast until center of stuffing registers 165 degrees on an instant-read thermometer. To bake all of the stuffing outside a turkey: Spoon into a buttered 2-quart baking dish. Cover dish with parchment paper-lined aluminum foil. Bake at 400 degrees for 20 minutes. Uncover and bake until golden brown, about 25 minutes more.