Make Ahead Tip: Bake, let cool for 1 hour, cover with foil and refrigerate for up to 3 days. Reheat, covered, in a preheated 350°F oven for 45 minutes.
Ingredient note: Like fresh mushrooms, dried have a shelf life. When purchasing them, look for whole mushrooms in the package without a lot of powdery dust or spiky shards; the color should be uniformly brown. Porcini can also be purchased online from Oregon Mushrooms at oregonmushrooms.com.