On a recent Sunday afternoon, Ellen Kassoff Gray was passing through the dining room at Equinox, which she co-owns with her husband, chef Todd Gray, when something sitting on a diner’s bread plate caught her eye: a white Alba truffle the size of a silver dollar with a bite taken out of it.

Earlier that day, chef Gray had placed a few of the pricey fungi in a glass case to promote the restaurant’s new offering, available now through January — a vegan brunch buffet with truffle shavings for a $20 surcharge. The diner must have mistaken the floor models as up for grabs.

Kassoff Gray politely approached the diner, who told her she didn’t like the taste and suggested the chef salvage the unbitten part.

“I took it over to Todd and showed him, and he said, ‘That’s a $300 bite!’” Kassoff Gray says. “It was one of the costs we had to eat, literally.”

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