A conversation with Marie Brennan about fungi on a blustery day in late March was swift, targeted and overwhelmingly shroomy. That’s shroomy in the best sense of the word, referring to the mushrooms, wild foraging and plant-based foods that have triggered surging public interest in mycological activities, cuisine, history and culture.
Brennan grew up on a dairy farm in Baraboo, Wisconsin, and at age 14 embarked on the life of a vegetarian. Introduced to quinoa, miso and other delectable edibles two years into her culinary journey, she became a vegetable enthusiast, keen fermenter and avid investigator of the million-and-one ways cooking and eating mushrooms and other yummy plant-based foods can go right—or wrong.
Ever the hedonistic adventurer, after earning a bachelor’s in dietetics from the University of Wisconsin, Brennan took off for South Korea to teach English at a public middle school. Four years in classrooms provided the best education possible for effective teaching. Upon returning to the United States, she studied culinary arts at Berkeley’s Bauman College. Brennan then became a certified natural chef. And now, in 2024, she is an educator, consultant, private chef and recipe developer.
This means a sold-out “Magnificent Mushrooms” class, with its eager participants waiting across the Bay Bridge at the 18 Reasons nonprofit cooking school in San Francisco. “We have about 25 minutes to talk,” she said. “And yes, the class sold out immediately, and there’s a huge waiting list. The interest is partly because people know mushrooms are good for you and partly because more people are interested in plant-based foods along with personal care items and other things.
“They may want to be vegan or vegetarian, or not,” Brennan added. “But regardless, people are looking for good meat substitutes like mushrooms that have a lot of umami, that earthy flavor associated with a satisfying taste and the feeling of fullness. Mushrooms have a texture that’s chewy, similar to meat, but not involving animals. It’s sometimes called ‘Buddhist meat’ for those and other reasons.”
In her work with students and clients, and from her research of public opinion, food movements and preferences, Brennan has found texture, not taste, to be the most divisive feature of mushrooms.
“Most of the time people who dislike mushrooms say they’re gummy and gross,” she said. “One guy in my mushroom class who was in his mid-50s told me he hadn’t touched a mushroom since seventh grade. We prepared my Shiitake Bacon, and I went over to his table first for the tasting. He picked a piece up, put it in his mouth and said, ‘This is delicious.’ I say learning to prepare them properly is essential.”
The recipe and cooking methods for Brennan’s “secret weapon” bacon are often included in courses like the one she’s teaching later in the day. Along with the “Magnificent Mushroom” course’s King Trumpet Cioppino, Mixed Mushroom Miso Toasts, a warm salad, and a sweet-and-savory shortbread that all feature mushrooms, students will learn to prepare a dish that incorporates Shiitake Bacon.
Brennan said it has the crunch and salty savoriness of bacon and can be made with a variety of mushrooms, from shiitake to oyster, king trumpet and even crimini blossom mushrooms. The simple, three-step recipe—available under “recipes” at Brennan’s website at hedonistinmoderation.com—she said results in something akin to “fairy dust” that “will transform a lackluster dish into a shining star.”
Along with learning to maximize and highlight the best flavors and textures of cooked mushrooms, education about the inherent dangers of foraging and consuming found fungi is vital. Eating poisonous mushrooms or toadstools can be lethal, especially for children. Their smaller bodies are more sensitive to toxins at lower levels in all foods than the toxicity levels established for adults.
Organizations such as the Mycological Society of San Francisco and the Bay Area Mycological Society are good resources for information related to fungi. Both entities offer lectures, classes, workshops, fungi fairs, memberships with added benefits, and extensive information and resources available to anyone online and at in-person events.
In separate interviews held before MSSF’s annual fungus fair in December 2023, American mycologist, naturalist and writer David Arora and Dr. Kathryn Meier, senior toxicology management specialist with the California Poison Control System, spoke about the broad interest in mushrooms and foraging.
Arora said access to legal wild mushroom foraging on public lands in the coastal regions of California is limited, as is the general public’s accurate knowledge about dosages, varieties, best practices and regions for wild mushrooming. He said moderation is always necessary—“You want 100% accuracy about safety if you’re going to be eating a mushroom”—and noted that if more people were educated and the information available online consisted of science-based facts and less misguided advice, mycological foraging could be safer, more widely practiced and enjoyable.
Meier said most of the serious toxic exposures she sees are people who are inadequately trained and have mistakenly consumed a mushroom that is inedible and poisonous. Importantly, some poisonous mushrooms do not cause immediate symptoms but instead, the toxins slowly develop in the body and will eventually destroy the liver. By the time the source of a liver condition is identified, she said it is often “too late: a cart already out of the barn.”
Parents of toddlers especially should guard their young children who, seeing a bright blue mushroom in the backyard, might pluck it from the ground and consume it in seconds, Meier said. Like Arora, she suggested using resources and links available at mycological organization websites and information online at California Poison Control System (calpoison.org) that provides accurate and fast advice concerning poisonings.
Brennan reiterated Arora’s points: that mushroom foraging is not allowed in any of the East Bay regional or state parks, and the importance of self-education based on expert science.
“You can go to Sonoma, but even there, where it’s allowed, I took a class through SF Forager and we found a lot of turkey tail,” she said. “I advise you to not even try foraging unless you do your homework, learn and follow legal directives, and utilize expert knowledge, either through digital means or by having a guide. Above all, do not eat any mushroom unless you are completely sure it’s not poisonous.”
In the classroom, there’s less talk about toxicity than about taste. “There are two things I hammer in my classes,” Brennan said. “The first is maximizing flavor with heat, which breaks down the amino acids, the proteins. When it’s slow, dry heat—roasting them instead of cooking them in soup on the stovetop—you create awesome textures. You can crisp them like bacon, or stop short of crispiness and they’re more chewy, like meat jerky. Mushrooms extend well beyond stir-fries or dumping them in soup.”
And on the rare occasions when Brennan steps out of her test kitchen and allows someone else to do the cooking? “I like Daytrip in Temescal for its inventiveness, local ingredients and whimsical atmosphere,” she said, adding, “I use Shared Culture’s miso in San Francisco for my recipes because they use local foraging.” And in a follow-up email, Brennan added two more favorite go-to restaurants: Pyeon Chang Tofu House and Pizzaiolo.
In the East Bay, restaurants, markets, and expert chefs and educators like Brennan mean there’s plenty of opportunity and good reason to jump on the wagon and explore the wonderful world of mushrooms. When someone’s name hits the top of the waiting list, they’ll be cooking magic bacon in no time.
