The newly renovated San Francisco Museum of Modern Art is home to thousands of pieces of original art — but when it comes to the food offerings, there may be some forgeries in the mix, too.

Like many other Bay Area residents, pastry chef Caitlin Williams Freeman took her maiden tour of the museum last week. The former art student and recently renewed SFMOMA member marveled at the breathtaking architecture and labyrinth of art, but when she reached the fifth-floor eatery and sculpture garden — now dubbed Cafe 5 — her heart dropped.

“I walked up and was like, ‘Wait, what? What are these desserts?’” said Freeman.

There, right on the Cafe 5 menu, was an entire section dedicated to “art-inspired cakes,” with sweets mimicking individual art pieces, such as a peanut-butter-and-banana cake named after Andy Warhol’s “Triple Elvis” and a slab of layered fruit creams based on Ellsworth Kelly’s “Gaza.”

According to Freeman, the cakes are a direct rip-off of the desserts she once created in that very same cafe on the very same floor of the museum.

Blue Bottle Coffee opened a cafe in the space in 2009, and Freeman quickly gained national attention there for her playful and innovative desserts, which were visually and thematically inspired by the adjacent art pieces. There was a Thiebaud cake — a yellow layer cake with raspberry buttercream frosting — and a trifle based on Richard Diebenkorn’s “Ocean Park” series. Most notable, perhaps, was the Mondrian cake, each slice interspersed with squares of yellow, white, blue and yellow, separated by dark chocolate lines. It turned into an online viral sensation — and graced the cover of Freeman’s 2013 cookbook, “Modern Art Desserts.”

‘Beautiful thing’

Essentially, Freeman invented a genre of pastry in the shoebox-size kitchen on the rooftop of the museum.

“I thought that’s what museums are for — their job is to inspire people. I was so inspired,” said Freeman, who worked with two other pastry chefs on the desserts. “We opened a cafe and did this beautiful thing and felt really deeply about it.”

But when the museum closed for remodeling in 2013, it forced Blue Bottle to reapply for the cafe position. Freeman — and her husband, Blue Bottle founder James Freeman — wanted desperately to stay, and they estimate they spent roughly $20,000 going through the proposal process, given architectural renderings, labor costs and menu tastings.

In the end, SFMOMA declined to have Blue Bottle return, opting instead to give a third-floor coffee bar to a fellow local coffee roaster, Sightglass.

The operation of the fifth-floor cafe, meanwhile, went to McCalls Catering, which had previously run the now-defunct ground-floor cafe, Caffe Museo.

That history — the rise of the cafe’s art-inspired cakes, followed by the museum’s subsequent rejection of Blue Bottle — made Freeman’s discovery of the knockoff desserts sting even more.

“If they didn’t want what I was doing, then why is this happening?” Freeman said. “It makes me not want to go back to the museum, but it’s so beautiful.”

As of Friday, three art-inspired cakes remained on the Cafe 5 menu. None is an exact replica of Freeman’s creations — there is no Mondrian cake, for example — but the lineage remains clear, said Freeman. For example, a chocolate-studded simulacrum of the museum’s iconic turret is a dessert that bears a striking, if markedly less elegant, resemblance to a layered dessert created by Freeman for a press event announcing SFMOMA’s expansion plans several years ago.

McCalls Catering, which is producing the cakes, was quick to brush questions aside.

“There is no controversy,” said McCalls President Lucas Schoemaker. “It’s SFMOMA who needs to answer all these questions.”

He would not comment further.

Re-creating famed dishes

In the food world, copying dishes is a given, and usually one with little legal recourse. That said, it is often professional courtesy to credit the creator of a dish — a conceit that will, coincidentally, fuel the new museum’s new ground-floor restaurant, due to open next month, where noted local chef Corey Lee will re-create, and directly credit, dishes from famous chefs around the world.

That’s not the case at Cafe 5. Freeman sent the museum a letter last week, getting a reply that said while she isn’t the only person to be inspired by art in a museum cafe, they would consider asking McCalls to stop serving the cakes. SFMOMA representatives have not responded to Chronicle inquiries.

“It’s so tacky and so gross, but there’s kind of nothing I can do about it,” said Freeman, with a laugh. “I guess I just have to feel good that I wrote the goddamn book on art desserts.”

Paolo Lucchesi is The San Francisco Chronicle’s food editor. Email: plucchesi@sfchronicle.com Twitter: lucchesi