1 pound short pasta, such as rotini or gemelli
6 tablespoons unsalted butter, divided
1 lb mushrooms, sliced
4 tablespoons all-purpose flour
2 cups whole milk
2 cups chicken or turkey stock
2-3 cups leftover turkey, shredded
1/2 teaspoon cayenne pepper
1/2 teaspoon rubbed sage
1/4 teaspoon freshly ground nutmeg
salt and pepper
1 cup regular bread crumbs
1/2 cup grated Parmesan
3 tablespoons unsalted butter, melted
Preheat the oven to 350 degrees F. Lightly butter your baking dish or spray with vegetable oil. The full recipe uses a 9×13 pan but you can make a smaller amount and freeze the rest.
Cook the pasta in plenty of boiling, salted water until it has softened a bit but is still not quite cooked all the way through. (The pasta will absorb the liquid from the sauce as it finishes cooking in the oven.) Drain, rinse with cold water to stop the cooking and set aside.
In a large skillet, melt two tablespoons of the butter and sauté the sliced mushrooms. Once they have released their liquid and most of it has evaporated (about 10 minutes), remove from pan and set aside.
Add the remaining butter to the skillet and melt it over medium heat. Add the flour and whisk to combine. Whisk constantly until the flour has cooked but not browned, about 2 minutes. Add the milk slowly, whisking to avoid creating any lumps. When it comes to a simmer, add the chicken stock, cayenne and nutmeg and cook, stirring frequently, until the mixture begins to thicken, about 5 to 10 minutes. Stir in the sage and season with some salt and pepper. Fold in the mushrooms, turkey and pasta, making sure it is all well coated with the sauce. Pour into the prepared pan.
To make the topping, combine the bread crumbs and Parmesan and moisten with the melted butter. Spread topping evenly over the tetrazzini, put the pan into the oven, and cook until the top is golden brown and the mixture is bubbling, about 30 minutes. Let rest for 10 minutes before serving.