THERE ARE SOME (MAINLY IN SAN FRANCISCO) WHO refute the claim that this rich, creamy casserole was created in Charleston, South Carolina, shortly after the turn of the twentieth century for the famous coloratura soprano Luisa Tetrazzini, but whatever the dish’s regional origin, it has come down as one of the South’s most classic and beloved casseroles. Unlike most casseroles, a tetrazzini is never layered but simply tossed, and what gives the dish its distinct identity over its obvious Italian cousin (spaghetti with a ragù sauce) are not only the diverse ingredients but also the way it’s baked till crusty. Leftover turkey, ham, or a mixture of meats can be used to make this tetrazzini, and no unbaked casserole freezes so beautifully till ready to be thawed, baked, and served.

Makes 6 servings

INGREDIENTS

• 6 tablespoons (3⁄4 stick) butter
• 1⁄4 pound fresh mushrooms, chopped
• 1⁄4 cup all-purpose flour
• 1 teaspoon salt
• Freshly ground black pepper to taste
• 1⁄4 teaspoon ground nutmeg
• 1 cup chicken broth
• 1 cup half-and-half
• 2 pounds cooked chicken, cubed
• 1 cup black olives, drained, pitted, and chopped
• 1⁄2 cup slivered almonds
• 1⁄2 cup freshly grated Parmesan cheese
• 1 large egg yolk, beaten
• 7 ounces spaghetti, cooked according to package directions (but not more than 8 minutes) and drained

INSTRUCTIONS

1. Preheat the oven to 350°F. Butter a 2- to 2 1⁄2-quart casserole dish.
2. In a small skillet, melt 2 tablespoons of butter over moderate heat.
3. Add the chopped mushrooms to the skillet and stir for 5 minutes. Remove from heat.
4. In a large, heavy pot over moderate heat, melt the remaining 4 tablespoons of butter.
5. Add the flour, salt, pepper, and nutmeg to the pot. Cook, stirring, for 1 minute.
6. Gradually add the chicken broth and half-and-half to the pot. Cook, stirring, until the sauce begins to thicken, about 5 minutes.
7. Remove the pot from heat and add the cooked chicken, black olives, almonds, cheese, and beaten egg yolk. Stir until well blended.
8. Place the cooked spaghetti in the buttered casserole dish.
9. Pour the chicken mixture over the spaghetti and toss to mix well.
10. Bake the casserole until the top becomes crusty, approximately 25 to 30 minutes.
11. Serve the dish hot.