Meaty mushrooms proudly stand in for meat in this vegetarian riff on the classic Italian meat sauce. Glantz uses a blend of locally sourced wild mushrooms here, but any mix of fresh mushrooms will do. However, be sure to seek out dried porcini mushrooms; after a quick soak in steaming hot water, they plump up and release their intense, heady flavor into the soaking liquid, which adds a rich depth to this sauce. For extra umami, toss in a Parmesan rind while the sauce cooks. It's a good practice to keep leftover Parmesan rinds in the freezer for just this purpose.