Recipe: Twice-Baked Sweet Potato Casserole

8 to 10 servings

- 2 ½ pounds sweet potatoes

- 2 pounds yams

- 5 tablespoons unsalted butter at room temperature, divided

- ¾ cup milk

- ¼ teaspoon ground cinnamon

- 1 ¾ teaspoon kosher salt

- ½ teaspoon freshly ground black pepper

- 2 teaspoons minced fresh thyme leaves

- 1 ½ teaspoons minced fresh rosemary leaves

1. Preheat oven to 350 degrees. Line center oven rack with a sheet of aluminum foil. Rinse sweet potatoes and yams; pierce in several places with a paring knife and place on foil-lined rack. Bake 1 to 1 ¼ hours or until very tender. Remove from oven.

2. When vegetables are cool enough to handle, cut in half and scoop the pulp into a large bowl. Add 4 tablespoons butter, milk, cinnamon, salt, pepper, thyme, rosemary and lemon juice. Mash until smooth with a potato masher, or with an electric mixer. Spoon into a 2 ½-quart casserole dish and dot with remaining tablespoon butter. (The dish can be covered and refrigerated up to 24 hours.)

3. Preheat oven to 350 degrees. Remove the casserole from the refrigerator 30 minutes before baking. Uncover and bake on center rack 30 minutes, or until heated through. For a browned topping, run under a hot broiler.