Nick Loeb — whose stunning former fiancée Sofia Vergara has run into the rippling arms of Hollywood hunk Joe Manganiello — is determined more than ever to become king of the condiment world. But his guerrilla marketing tactics at a Hamptons food festival to promote his Onion Crunch topping had some foodies grousing he was trying to monkey with their dishes.

Loeb’s past efforts to push the crunchy creation landed him in hot water with Vergara — including the time she brought him as a date to meet President Obama and he slipped the stuff to the White House’s chef at dinner. With Vergara gone, presumably so are the tears over his onions. But some Hamptons chefs cried foul at the tony Taste of Two Forks on Saturday when Loeb arrived as an invited guest and was secretly armed with a backpack of his newest creation, Pickle Crunch.

Tickets to Taste of Two Forks, where 40 top chefs serve up gourmet grub, cost $160 or $240 for a VIP package. “Nick didn’t pay to be a part of it,” sniffed one attendee. “He wasn’t a sponsor or participant. But he arrived with a backpack of this ‘Onion Crunch Pickle’ and was going around putting it on all the tables.”

“These chefs go to a lot of trouble, and cost, to create their dishes with their own particular seasonings,” seethed our spy. “For someone to add such a, shall we say, vibrant, condiment would throw a dish into another other direction.”

But a source close to Loeb insisted, “Nick was doing what any businessman would do, promote a new product. Especially when their brand is a crunchy condiment.” And, “He was not putting Pickle Crunch on anyone’s tables. He was handing it to some of the chefs in back, behind the scenes, to introduce them to a new product to try for future use. He didn’t even have that much.”

Organizers said Loeb was invited as a guest but not as a participant. The day was hosted by Katie Lee and Geoffrey Zakarian and included dishes by chefs including Gurney’s Seawater Grill’s Seth Levine and Sienna’s Donatella Arpaia, while official sponsors included meat maestro Pat LaFrieda.