We used grocery rotisserie chickens for this recipe, but leftover turkey from the holiday table works equally well—or check out our simple Turkey Tetrazzini recipe.

　　

Ingredients

Makes 6 servings

　　1 to 1 1/2 pound chicken bones (from 2 cooked chickens), broken into 2- to 3-inch pieces

　　4 cups low-sodium chicken broth

　　1 carrot, thinly sliced

　　1 medium onion, coarsely chopped

　　2 celery ribs, cut into 1-inch pieces

　　2 garlic cloves, smashed

　　5 whole black peppercorns

　　1 Turkish or 1/2 California bay leaf

　　2 whole cloves

　　3/4 stick (6 tablespoons) unsalted butter

　　3/4 pound mushrooms, thinly sliced

　　1/2 teaspoon salt

　　1/4 teaspoon black pepper

　　2 tablespoons all-purpose flour

　　1 cup heavy cream

　　3 tablespoons medium-dry Sherry

　　2 tablespoons truffle butter* (optional)

　　1/2 lb spaghetti

　　2 pounds chicken meat (from 2 cooked chickens), torn into 1-inch pieces

　　1 ounce freshly grated Parmigiano-Reggiano (1/2 cup)

　　

Step 1

Bring chicken bones, broth, carrot, onion, celery, garlic, peppercorns, bay leaf, and cloves to a boil in a 3- to 4-quart heavy saucepan, then simmer, partially covered, skimming froth, 30 minutes.

　　

Step 2

Pour stock through a large sieve into a bowl, discarding solids, and return to saucepan. Measure stock: If more than 2 cups, boil until reduced. Keep warm, covered.

　　

Step 3

Put oven rack in middle position and preheat oven to 350°F. Butter a shallow 3-quart glass or ceramic baking dish.

　　

Step 4

Heat 3 tablespoons butter in a large heavy skillet over moderately high heat until foam subsides, then sauté mushrooms with 1/4 teaspoon salt and 1/8 teaspoon pepper, stirring, until liquid mushrooms give off is evaporated and mushrooms begin to turn golden, about 8 minutes.

　　

Step 5

Melt remaining 3 tablespoons butter in a 2- to 3-quart heavy saucepan over low heat, then add flour and cook roux, whisking, 3 minutes. Add warm stock in a fast stream, whisking constantly, and bring to a boil. Reduce heat and simmer, whisking occasionally, 5 minutes. Add cream, Sherry, remaining 1/4 teaspoon salt, and remaining 1/8 teaspoon pepper and simmer over low heat, whisking occasionally, 10 minutes. Stir in truffle butter (if using).

　　

Step 6

Cook spaghetti in a large pot of >boiling salted water until al dente, then drain well.

　　

Step 7

Toss together spaghetti, mushrooms, and half of sauce in a large bowl, then transfer to baking dish. Stir together chicken meat and remaining sauce in same large bowl. Make a depression in spaghetti, then spoon chicken into it and sprinkle dish with cheese.

　　

Step 8

Bake until sauce is bubbling and top is lightly browned, about 30 minutes. Serve immediately.

　　

Step 9

*Available at some specialty foods shops and D'Artagnan (800-327-8246).

　　Cooks' notes:

　　·Mushrooms can be sautéed 1 day ahead and chilled, covered. Bring to room temperature before using.

　　·Sauce can be made 1 day ahead and cooled completely, uncovered, then chilled, its surface covered with wax paper.