Turkey Tetrazzini
Serves 8

Tetrazzini is also great when made with leftover chicken. Using a shallow baking dish without a cover and a very hot oven benefits both texture and flavor. Don’t skimp on the salt and pepper; this dish needs aggressive seasoning. To make fresh bread crumbs, trim crusts from about 8 slices of good-quality white bread (we like Pepperidge Farm Toasting White) and grind them in the food processor until evenly fine-textured, 20 to 30 seconds.

bread crumb topping
1½ cups fresh bread crumbs (see note)
Pinch salt
4 tablespoons unsalted butter, melted
¼ cup grated Parmesan cheese

filling
8 tablespoons unsalted butter, plus extra for baking dish
8 ounces white button mushrooms, cleaned and sliced thin (about 3 cups)
2 medium onions, chopped fine (about 1½ cups)
Salt and ground black pepper
¾ pound spaghetti or other long-strand pasta, strands snapped in half
6 tablespoons unbleached all-purpose flour
3 cups canned low-sodium chicken broth
4 tablespoons dry sherry
¾ cup grated Parmesan cheese
¼ teaspoon grated nutmeg
1 tablespoon juice from 1 lemon
2 teaspoons minced fresh thyme leaves
2 cups frozen peas
4 cups leftover cooked boneless turkey or chicken meat, cut into ¼-inch pieces

1. For the topping: Adjust oven rack to middle position and heat oven to 350 degrees. Mix bread crumbs, salt, and butter in small baking dish; bake until golden brown and crisp, 15 to 20 minutes. Cool to room temperature and mix with ¼ cup Parmesan in small bowl. Set aside.
2. For the filling: Increase oven temperature to 450 degrees. Heat 2 tablespoons butter in large skillet over medium heat until foaming subsides; add mushrooms and onions and sauté, stirring frequently, until liquid from mushrooms evaporates, 12 to 15 minutes. Season with salt and pepper to taste; transfer to medium bowl and set aside. Clean skillet.

3. Meanwhile, bring 4 quarts water to a boil in large pot. Add 1 tablespoon salt and pasta and cook until al dente. Reserve ¼ cup cooking water, drain spaghetti, and return to pot with reserved liquid.

4. Melt remaining 6 tablespoons butter in cleaned skillet over medium heat. When foam subsides, whisk in flour and cook, whisking constantly, until flour turns golden, 1 to 2 minutes. Whisking constantly, gradually add chicken stock. Turn heat to medium-high and simmer until mixture thickens, 3 to 4 minutes. Off heat, whisk in sherry, Parmesan, nutmeg, lemon juice, thyme, and ½ teaspoon salt. Add sauce, sautéed vegetables, peas, and turkey to spaghetti and mix well; adjust seasonings to taste.

5. Turn mixture into buttered 9 by 13-inch gratin dish (or other shallow, ovenproof baking dish of similar size), sprinkle evenly with reserved bread crumbs, and bake until bread crumbs brown and mixture is bubbly, 13 to 15 minutes. Serve immediately.