Cheesy Mixed Pasta with Mushrooms

In a heatproof glass measuring cup, cover dried mushrooms with 1 cup of boiling water, allowing them to soften for about 20 minutes; then drain, reserving 3/4 cup of the soaking liquid, and finely chop the mushrooms.

Meanwhile, melt 4 tablespoons of butter in a large saucepan, then add the flour and cook over moderate heat, stirring until smooth, approximately 1 minute; whisk in the reserved liquid and milk, bring to a simmer, and cook over moderately low heat until thickened, about 5 minutes, before stirring in the cream and chopped mushrooms and scraping into a large bowl.

In a large skillet, melt the remaining 2 tablespoons of butter, then add the mushrooms, seasoning them with salt and pepper, and cook over moderately high heat until browned in spots, approximately 5 minutes; add the mushrooms to the sauce, stir in the pasta and cheese, and season with salt and pepper before scraping the pasta into an 8 1/2-by-12-inch baking dish.

Sprinkle with the Parmigiano and bake for approximately 35 minutes, until golden and bubbly, then let it stand for 5 minutes before serving.