A tray of coffee-grown oyster mushrooms can begin with something as ordinary as yesterday’s grounds. What would have become waste is now food with a firm bite and a deep sear. To get the tastiest meals, start with how to cook king oyster mushrooms, drawing inspiration from Japan, Korea, Italy, Thailand and the Mediterranean.
How to Cook King Oyster Mushrooms
Learning how to cook king oyster mushrooms begins with prep that helps them brown rather than steam. Brush off any dirt with a soft brush or damp paper towel instead of washing the mushrooms, since extra water can change their texture in the pan.
Trim the stem ends if they feel tough, then halve or slice the mushrooms. Heat one tablespoon of oil in a large skillet over medium-high heat. Once it’s hot, add the pieces in a single layer with plenty of room, because crowding makes mushrooms steam.
Leave them undisturbed for a couple of minutes, until they release their juices and start to brown. Then stir and cook for three to five minutes more, until golden and tender. Salt them near the end, since early salt draws out moisture and slows browning.
That golden browning is the key to cooking king oyster mushrooms well. Once browned, they can take on soy glaze, garlic butter, chili-lime sauce or herbs without losing their firm bite.
The Science Behind Mushrooms Grown on Coffee Waste
The mushrooms in your skillet may have started in a coffee cup, and we wanted to know how that happens. Oyster mushrooms are especially good at breaking down tough plant fibers, which is why growers can raise them on a wide variety of cellulose-rich substrates, from coffee grounds and old paper to cotton waste and sugarcane pulp.
Cafés and kitchens produce a lot of spent grounds every day, providing growers a steady supply to work with. Pairing that supply with a hardy mushroom makes for an easy match.
Why Spent Coffee Grounds Make Such a Great Growing Medium
Spent grounds in landfills give off methane as they decompose. That greenhouse gas is about 25 times stronger than carbon dioxide over a century, which gives coffee waste a large footprint. Fortunately, spent coffee grounds have a ton of uses, including promoting healthy soil for crops.
Spent coffee grounds contain high levels of nutrients, such as potassium and phosphorus, that soil microbes thrive on. Mushrooms love to soak up those nutrients when they grow.
Nutritional Benefits of Oyster Mushrooms
While sustainable, oyster mushrooms are also protein-rich and low in fat, so a skillet of them is great for a weeknight dinner. Their dry-matter makeup also includes these nutrients:
- Protein: Roughly 15% to 30% of their dry matter is protein.
- Carbohydrates: These make up the largest share, at roughly 43% to 60% of dry matter.
- Fat: Only about 1.2% of the mix is fat, keeping these mushrooms naturally light.
- Fiber: Their dietary fiber may support digestive health.
A World Tour of Mushroom Cooking Methods
We love how well these mushrooms handle fast cooking. Even Michelin-starred chefs are experimenting with rootlike oyster mushroom mycelium grown on coffee grounds.
Japanese-Style Tempura and Yakitori Oyster Mushrooms
Tempura wraps mushroom slices in a crunchy shell, while yakitori-style grilling adds a sweet-savory glaze. Cut king oysters into 1/2-inch slices for tempura or chunks for yakitori.
For tempura, whisk one cup of flour, one cup of ice-cold sparkling water and a pinch of salt until just combined. Dip the slices and fry them in batches in 375° Fahrenheit oil for two to three minutes. Drain them on a wire rack.
For yakitori, start the glaze first, since it simmers for about 45 minutes. Combine 1/2 cup each of mirin and soy sauce, 1/4 cup each of sake and dark brown sugar, and one tablespoon of rice vinegar. Add three garlic cloves, three scallions, a sliced one-inch piece of ginger and one tablespoon of peppercorns. Simmer until syrupy, then strain.
Brush the skewered chunks with oil and cook them covered over indirect heat for about 10 minutes. Then move them to direct heat, brush on the glaze and cook for one to two minutes.
Korean-Style Gochujang Seared Oyster Mushrooms
Gochujang, a fermented Korean chili paste, turns a simple sear into a glossy glaze in about 20 minutes. Whisk three tablespoons of soy sauce, two tablespoons each of gochujang and mirin, one tablespoon of sugar and three minced garlic cloves.
Toss 12 ounces of thick mushroom coins in half the sauce and let them sit for eight to 10 minutes. Sear them in two tablespoons of oil over medium-high heat for three to four minutes, then flip for two to three minutes more. Pour in the remaining sauce, reduce the heat and toss for one to two minutes. Off the heat, drizzle on one tablespoon of sesame oil. Serve over rice with sesame seeds and scallions.
Italian-Style Garlic Butter Oyster Mushrooms
Garlic and butter in a hot pan turn these mushrooms golden in about 15 minutes. Trim 1/2 inch off the stems of 1.5 pounds of oyster mushrooms, and halve or quarter the large ones. Brown half in one tablespoon of oil over medium-high heat for about four minutes, then set them aside. Repeat with the rest, return everything to the pan and cook for two minutes.
Stir in 10 thinly sliced small garlic cloves, two tablespoons of butter, 1/2 teaspoon of salt and 1/4 teaspoon of pepper for one minute. Off the heat, add 1/4 cup of chopped parsley and spoon everything over risotto.
Thai-Style Chili Lime Stir-Fried Oyster Mushrooms
Fish sauce and lime juice give this stir-fry a bright, salty tang after about 15 minutes of cooking. Halve one pound of mushrooms lengthwise and score the cut sides in a shallow crisscross.
Sear half cut side down in one tablespoon of avocado oil over medium-high heat for two to four minutes. Flip and cook for two to three more minutes, then repeat with the rest.
Lower the heat to medium and add one more tablespoon of oil. Stir-fry 1/2 cup of minced shallots, four sliced garlic cloves, two teaspoons of minced ginger and one sliced Thai chili for one minute. Return the mushrooms and toss in one tablespoon each of fish sauce and lime juice. Finish with one tablespoon each of minced cilantro, mint and Thai basil.
Mediterranean-Style Herb Grilled Oyster Mushrooms
Garlic, thyme and balsamic vinegar soak into king oyster mushrooms during a marinade before they hit the grill. Wipe nine ounces of mushrooms with a damp cloth and halve them lengthwise.
Mix three minced garlic cloves, 1/4 cup of balsamic vinegar, 1/4 cup of olive oil, one tablespoon of fresh thyme and 1/2 teaspoon of salt.
Stir in the mushrooms and refrigerate them for 30 minutes. Finally, thread them onto bamboo skewers and grill over indirect heat for eight minutes per side. We like them hot, straight off the grill.
Bring Global Flavor to Your Table Tonight
Grounds from a morning brew can come back to the table as chewy, golden coffee-grown oyster mushrooms. A crisp tempura coating, sticky gochujang glaze, garlicky butter sauce, chili-lime stir-fry or garlic herb skewer all show off a different side of their mild, meaty texture. Choose the method that fits your dinner mood, wipe a batch clean and get the pan hot tonight.
