Pasta with Fresh and Dried Mushrooms

Fresh porcini make the base of an incredible pasta sauce but cost at least twenty dollars a pound, if and when you can find them. Portobellos, which are cultivated, not wild, are sold at every supermarket every day at prices ranging from four to ten dollars a pound, and they’re consistent in quality. And if you cook them slowly in oil, adding a few reconstituted dried porcini as they cook—a technique popularized by Marcella