When Matt Robicelli’s rheumatologist told him he had to stop eating dairy, gluten and sugar, he did not take it well.

“I was like, ‘Why don’t you go f–k yourself,’ ” the 37-year-old chef tells The Post.

Those dietary restrictions would be bad news to anyone — especially a former bakery owner renowned for his buttercream cupcakes.

Now, he’s channeling his latest health challenge into another culinary adventure: Rip’s Malt Shop, a vegan comfort-food spot in Fort Greene, which he and his wife helped open in August.

“Food is life to me,” says Matt, who turned to culinary school after suffering severe injuries as a 9/11 first responder, which required reconstructive surgery on his left knee. In 2009, he and his wife, Allison, opened the dessert emporium Robicelli’s in Bay Ridge, where they both grew up. It quickly won over locals with its gooey cupcakes and decadent “Nutella lasagna.”

The sweet spot was doing so well that Matt and Allison were planning to expand the business — but in February 2016, disaster struck. Matt went to the hospital with chest pains. Tests revealed a mysterious, severe infection of the membrane surrounding his heart, which soon spread to several of his internal organs. The couple put their franchising plans on hold while Matt underwent intensive treatment and doctors tried to figure out the root cause of his illness.

“It’s really scary,” says Allison, 38. As a lymphoma survivor herself, who taught herself to cook while she was undergoing chemotherapy, she especially relates to his struggle.

Two years later, Matt’s still sick. Although he’s out of the hospital now, he suffers from severe abdomen pain, fatigue and intense fevers. His weeks are filled with doctor appointments and lab tests, and his medical team still doesn’t know exactly what’s wrong, but they suspect an autoimmune disease.

The only thing they know for sure is that gluten, dairy and sugar make it worse.

“It sucks,” says Matt, who officially slashed trigger foods from his diet six months ago at his rheumatologist’s behest. “It’s a lot of things [to have] taken away, and it gets really emotional.” He especially misses cheese, “my favorite food in the world.”

But it’s not all bleak. Matt’s allowed a little sugar once a week, and he’s got Allison’s full support — and, between the two of them, plenty of culinary creativity.

To benefit their health, the couple, now based in Baltimore, has gone mostly vegan. But they’re not resigning themselves or their two young boys to sad, bland meals. Instead, they’ve been figuring out how to make delicious food that fits Matt’s dietary needs, such as meatless “cheese” burgers and oat-milk milkshakes.

Their new passion for cleaner indulgences informs their latest NYC venture. Every few weeks, the pair travels from Maryland to check on the Brooklyn eatery, which is gaining raves for its vegan chopped cheese sandwich, loaded Tater Tots and cheery vibe.

It also features a few favorites from the couple’s old bakery — now veganized, Allison says.

“We’ve been able to alter a lot of [the] Robicelli’s recipes,” she says. Their brownies, for example, contain coconut oil and flax seeds soaked in water instead of eggs. “You’d be surprised at how much you can do without dairy [and] sugar.”

In addition to Rip’s, the Robicellis are working with Oaxaca Taqueria, a local chain with lots of plant-based options, and developing recipes for the Food Network — including dishes and desserts with ingredients Matt can no longer enjoy. In those cases, Allison says, she’ll do the final taste test, or the couple will invite friends over. And Matt still plays a pivotal role, she says. “We’ve been in the business for so long, you can sometimes tell [if something tastes good] by the scent or by consistency or touch.”

True, recipe testing has become a lot more complicated. But considering all that they’ve been through, things could be worse, the couple agrees.

“We both came close to dying really young,” Allison says. “We’re not going to sit back and be depressed … We just try to keep each other smiling.”