Let's talk a little about one of the lesser celebrated wild foragibles: the oyster mushroom (ostreatus pleurotus). This mushroom is wonderful for several reasons: it can be harvested nearly year round, it's easy to identify, it can be cultivated, and it's delicate anise aroma and soft, creamy texture are delicious. This mushroom is a go-to inexpensive option for many restaurants to elevate their plates.
How to identify an Oyster Mushroom?
Oyster mushrooms grow immediately following moisture and thrive in cool to warm temperatures (55 to 85 degrees high daily temperatures), thus can be found year round in some parts of the US. They also prolific in spring, summer and fall after thunderstorms, though may only last a week, as they can grow very fast and then become waterlogged or rotten or devoured by bugs or worms.
Oyster mushrooms are saprophytic fungi with a mycelium that colonizes dead or dying trees or simply dead rotting wood. You'll see them growing off the dying parts of a live trees or often growing along the trunk of a dead tree. I've found a woods right after a storm where almost every maple log laying on the forest floor was covered in oyster mushrooms. Had I harvest all of them, it would have been over 30 pounds of mushrooms harvestable in a couple hours. Up in northern Minnesota, they can be found predominantly on Aspen (often called "poplar") whereas in central and southern Minnesota, and much of the midwest, it is found on many varieties of trees, ranging from poplar to basswood to maples, willow, oak or hickory.
Oysters are fairly versatile. The younger delicate oysters are best sautéed with garlic and maybe some butter or just nice olive oil, then stirred into another dish or served simply with some greens . More mature ones can be sliced into long thing strips, battered and deep fried for some mushroom fries. uniformly but rather travel down the stem till they just sort of disappear. An oyster has a white to sometimes slightly lilac spore print . A typical oyster starts small like little nickels growing in a cluster on a tree, though in only a few days they grow full size into the size of a small seashell or large freshwater mussel shell. Once they get too large they are less appetizing, in my opinion, I try to only harvest them when they are smaller, but it's important not to confuse them with the tiny oysterlings, which are a similar-looking, tiny inedible mushrooms which also grow on logs.
There are many varieties of oyster, including a less appetizing edible oyster called the "elm oyster" as well as a prized edible the "golden oyster". Elm oysters (Hypsizygus ulmarius) are larger and tend to grow mostly in the fall on elm trees and have a much denser stem and mushroom that makes it chewy and less delicate in flavor and texture than a typical oyster. Golden oysters (Pleurotus citrinopileatus) are much like a typical oyster mushroom only they don't always grow quite as large and have a bright yellow cap. Oysterlings (Crepidotus sp. or Panellus sp.) are full grown once the size of a small oyster and will have their cap completely opened up and typically they grow as a large group of individuals all growing from their own stems. These should not be eaten, though they are not considered to be poisonous. Another look-alike is called angels wings (Pleurocybella porrigens) and can be differentiated, much like oysterlings, in that they grow as individuals and typically lack any semblance of a stem, not as a cluster from as central stem as oysters grow. Angel's Wings also grows exclusively on conifers, whereas oyster mushrooms grow exclusively on hardwoods--this is probably the easiest and most failsafe way to ensure proper identification. Angel's wings are widely consumed in southeast Asia and other parts of the world (including folks Stateside), although there have been some reports that, if eaten in large quantities, they can be poisonous and even deadly. I consider a mushroom generally not worth that kind of risk so this is one that I would recommend leaving in the woods!
How to Use Oyster Mushrooms in the Kitchen?
Oysters are fairly versatile in the kitchen. Before trying to do any preparation, first remove the stem, which tends to be very tough. Also, be careful to look for little little beetles (typically a member of the Staphylinidae family of "rove beetles") and their eggs between the gills, as well as checking for larvae in the flesh upon slicing. Typically, the larvae is only found in older specimens which have been around a while. A simple rinse or careful brush between the gills will remove the beetles and any eggs that may be present. At this point, the mushrooms are ready to be cooked up!
The younger delicate oysters are best sautéed with garlic and maybe some butter or just nice olive oil, then stirred into another dish or served simply with some greens or over toast. More mature ones can be sliced into long thin strips, battered and deep fried for some mushroom fries.
Because they can be found in such large quantity, oysters are a great substitute for any dish calling for cremini or common button mushroom. They can also be used freshly to make a stock or can be dehydrated (then ground) and used to add substance to a stock, serve as a stock base or even be used as a mushroom seasoning when cooking other dishes.