Porcini literally means "piglets" in Italian because of their plump little bodies as they are found on the forest floor. They hold a prime spot in Italian cuisine (often being called the king of mushrooms) and fresh mushrooms are quite heftily priced. The porcini have a high protein content, making them an excellent meat substitute in vegetarian/vegan dishes. They're supposed to have a chewy texture, and a strong nutty-woody meaty taste. In the US, its primarily found in small bags in dried form.
Buying and Reconstituting Dried Porcini Mushrooms: So here's what I've learnt about buying dried porcini from my research. Make sure that the bag has large chunks of porcini and not old crumbly pieces. Also makes sure that the bag has no holes, or signs of worms or mold. When I opened the package at home, there was a really strong, almost pungent, mushroom aroma that rose from them. If there is no smell, there is likely no flavor in them either. To reconstitute, bring half cup water, or vegetable broth to a rolling boil. Add mushrooms, swirl, cover and set aside for about 15 min. Remove mushrooms with tongs and set aside. Strain the steeping liquid through a fine mesh strainer, or cheese cloth. This liquid will bring a lot more of the lovely earthy flavor of the mushrooms to the recipe.