Life keeps getting better for mushroom lovers. Thanks to refined cultivation methods and an increasingly informed market of eaters and cooks, the menu of mushrooms available to shoppers has increased dramatically in the last two decades, with a recent flush of diverse offerings. One of the mushrooms you may see at your local grocery store is very distinctive: the king oyster, also known as the king trumpet. This unique mushroom has a huge, trunk-like white stalk, and its stem dwarfs its cap, which might make you wonder what you're paying for: Aren't mushrooms stalks tough? Not in this case. That stout stipe (mushroom-speak for stalk) is scallop-like and delicious.
The mighty king oyster belongs to the Pleurotus eryngii species-complex (which means it's complicated and scientists are still classifying different species). It has a flock of other English common names: In addition to being dubbed the king oyster mushroom, it's also known as the king trumpet, French horn, royal trumpet, and scallop mushroom. King oysters bear little physical resemblance to their close cousins, oyster mushrooms, which grow in shelf-like clusters; instead, they produce a mushroom with a small, round cap and a defined, central stem, disproportionate in size to that diminutive cap. Also, unlike more perishable oyster mushrooms, the thick-stemmed, short-gilled king oysters have a very long shelf life and will stay fresh for weeks if kept covered and chilled.
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The king oysters' good flavor and texture, long storage life, and the daily PR machine that is social media have created an audience that is more familiar with the mushrooms; now, U.S. growers are beginning to keep pace. One advantage of sourcing domestically-grown king oysters is that they are fresher, since imports often sit in cargo holds for weeks en route to market.
Wild king oyster mushrooms occur naturally around the greater Mediterranean, where they grow in close association with plants in the Apiaceae family (often also referred to as umbellifers), especially Carduus (cardoons) and Eryngium (sea holly, and the source of the species name). They were first cultivated in Sicily (where they are called cardoncello, after that cardoon) and are now produced mostly in China, Japan, and Korea. For U.S. shoppers, king oysters are available in some grocery stores and they are reliably found in Asian markets in big cities or online. Interestingly, cultivated forms of king oysters vary in appearance depending on how they are grown. They may have bulbous, porcini-like stalks, or longer, straighter stalks. Those grown indoors with minimal fresh air and low light are paler and have much thicker stalks and smaller caps than wild-foraged specimens, or mushrooms exposed to lots of fresh air and light, and whose "feet" are smaller, with larger and darker caps and gills.
The firm texture of king oyster mushroom stems makes them excellent candidates for the grill. Slice them thickly lengthwise, baste them with soy sauce, and cook them until golden. Another option is to treat them like the scallops, whose texture and flavor they resemble: Slice the plump stems into fat medallions, then sauté in butter or oil. They respond beautifully to a cornucopia of herbs and spices, too; once the king oysters are sizzling, turn to your window box for basil and thyme, or go South Asian with a dusting a garam masala or a commercial curry powder blend. Think Sicily: chile-heat and fresh lemon; or try a Middle Eastern accent with baharat and a squeeze of orange juice. Cooked low and slow king oysters make sumptuous pie fillings, and they sop up sauces and flavors in the way that makes tofu so versatile.
King oysters may have a future as anti-depressant supplements (although so far only mice have benefited, in studies). And they possess the beneficial therapeutic attributes that makes the Pleurotus genus in general so interesting, with antibiotic, antiviral and anti-cancer potential, cholesterol-limiting properties and cardiovascular benefits. In short, they are delectable medicine.