The beef Wellington in RecipeTin Eats’ acclaimed debut cookbook, Dinner, once stood as a testament to founder Nagi Maehashi’s meticulous approach to trial-and-error recipe development.

“I’m proud to say I’ve finally cracked one of the trickiest of haute cuisine classics, the grand beef Wellington,” Maehashi wrote on her RecipeTin Eats website in 2022. “The end result is incredibly juicy, edge-to-edge rose pink beef encased in pastry boasting a flawlessly crispy base.”

Though the self-taught cook once baked 89 variations on a vanilla butter cake before publishing the recipe to her site, it was her beef Wellington that had taken the longest amount of time to perfect.

But over the past nine weeks, Maehashi’s labour of love became the signature dish in the so-called mushroom murder trial of Erin Patterson.

On Monday, a jury found Patterson, 50, guilty of murdering her parents-in-law, Don and Gail Patterson, and Gail’s sister Heather Wilkinson, and attempting to kill Heather’s husband Ian Wilkinson, who survived, at her home in the Victorian town of Leongatha in 2023.

Patterson told the court she used Maehashi’s beef Wellington recipe to prepare the deadly lunch, but substituted button mushrooms for portobello mushrooms and added “dried mushrooms … bought from the grocer” because the duxelle (sauteed mushroom mix) “seemed a little bland”. The prosecution argued Patterson knowingly used poisonous death cap mushrooms.

Maehashi took to social media on Tuesday to plead for privacy following the court’s judgment.

“It is of course upsetting to learn that one of my recipes – possibly the one I’ve spent more hours perfecting than any other – [and] something I created to bring joy and happiness, is entangled in a tragic situation,” Maehashi wrote to her 2.5 million Instagram followers.

“Other than that, I have nothing to say and I won’t be talking to anyone.”

But the macabre association seems to have increased interest in the dish. Beef Wellington has become a top-ranking Google search term in the days following the guilty verdict, and social media users turned to Reddit to discuss where to find the best beef Wellingtons.

At Canvas, the rooftop restaurant at the Museum of Contemporary Art in Sydney, head chef James Scott says his signature “lambington” dish has become a bestseller. It takes inspiration from a beef Wellington – swapping beef for lamb, and mushrooms for haggis, a savoury pudding based on sheep organs, onion and oats, encased in golden pastry.

“Our Australian customers have definitely made a few jokes like, ‘Oh, hopefully you don’t use those special mushrooms’. It’s just a coincidence that we don’t use mushrooms at all – though the haggis looks quite similar, and it has a very savoury flavour.”

“Foraging for mushrooms is much more common in other parts of the world than it is here in Australia because Australians are, in general, fearful of wild mushrooms.”

Robbie Robinson, professional mushroom forager.

Mornington Peninsula mushroom grower Dave Walford, of Mushroom Forestry, grows a range of mushrooms, including pioppino, shiitake, oyster and lion’s mane, and says building trust is important.

“I think some people are a bit cautious about the product at the moment,” he says. “Our customers haven’t stopped eating mushrooms and our sales have remained the same. I think it comes down to having trust in the person that’s growing your food or supplying your food.”

Robbie Robinson, a professional mushroom forager with more than 40 years’ experience, says the case may have triggered a long-held fear among Australians.

“Foraging for mushrooms is much more common in other parts of the world than it is here in Australia because Australians are, in general, fearful of wild mushrooms,” he says.

“I think the case has probably cemented that a little bit more in people’s minds the fact that wild mushrooms are something you must be very careful of.”

At the South Coast Fungi Feastival, held in NSW from mid-June to mid-July, all but one mushroom dinner has sold out, says organiser Annette Kennewell.

“All of our events have been really, really popular … and the only remaining seats are for our truffle feast with Gulaga Gold Truffles at Oaks Ranch [in Mossy Point on July 18].”

Kennewell, who plans to extend the program in 2026 to include mushroom foraging, says most people are aware of the difference between safe and unsafe mushrooms.

“People are smart enough to know that there’s a difference between someone who deliberately went out and chose a death cap mushroom to poison and kill people, versus people who are buying their mushrooms either in reputable supermarkets or at reputable farmers markets,” she says.

In Melbourne, Buttons is the owner-operator of The Mushroomery, an urban farm that regularly sells cultivated mushrooms at farmers’ markets in Coburg, Carlton and Alphington.

During the Patterson trial, a woman approached Buttons to comment on her ‘Mushroomery’ T-shirt: “She came up in front of me and looked at me, and said ‘Are you a murderer?’ I was like, ‘No, I’m a mushroom farmer,’ and she said, ‘Well, it’s pretty suspicious.’

“I think she was trying to make a joke, but it was really bad humour, accusing somebody of murder in the market.”

Buttons says sales have declined since the trial, but only among new customers.

“People aren’t as adventurous as usual,” she says. “But our regular client base is really solid.”