When the third course of spicy meatballs — prepared by chef Neal Fraser — was sent out to the communal dining room, food blogger Danielle Salmon knew something was off.

She and 40 other “food influencers” from Southern California were promised a free five-course meal prepared by the well-regarded Los Angeles chef and former “Top Chef Masters” contestant. As they arrived Wednesday night at the historic Carondelet House in downtown Los Angeles, the culinary writers and photographers were told the evening would end with a slight twist.

Fraser told them he would be “cooking with experimental” and “fresh” ingredients.

“Nothing sneaky,” said the chef-owner of Redbird, a seasonally influenced Los Angeles restaurant focusing on modern American cuisine.

Unbeknownst to the foodie fanatics gathered in the 1928 Italian villa, Fraser would be serving them an upscale meal made with McDonald’s ingredients. Using foods that make up hero McDonald’s products such as Quarter Pounders and Egg McMuffins, Fraser’s tasting menu included a chilled avocado soup, a buttermilk dressed romaine salad with bacon bits and bacon-wrapped chicken.

Midway through the meal, food blogger Salmon said her table began to wonder what was going on.

“It seemed a little off from what he normally serves,” said Salmon, “Chief Eating Officer” for a restaurant discovery blog called “Follow My Gut.” “We were thinking it was a weird secret ingredient.”

Throughout the room, others began to nitpick and speculate.

Some asked: Is it tofu? Is it synthetic food? Is he testing new dishes for a new restaurant?

“I’m trying to think what the heck is this experiment,” one male diner said.

Behind the scenes, a handful of McDonald’s operators could hear the chatter as they watched the dining event from a live feed in another room. With blessings from McDonald’s headquarters in Oak Brook, Ill., marketing officials for 600 local Southern California restaurant operators thought the secret dinner would shed new light on McDonald’s food.

Hidden cameras and microphones captured the foodies eating with gold flatware in an elegant farm table setting. A video of the event will be posted online later this month.

The goal: change the way people think about McDonald’s food.

“Unfortunately the perception is that it (our food) comes through the back door processed,” said Clay Paschen III, president of the McDonald’s Operators’ Association of Southern California. “But we cook. We have a kitchen. Starbucks doesn’t.”

As the publicity stunt formulated, Fraser was approached to pull it off.

At first, he declined.

“How do you change people’s perception?” he said before the five course dinner is served.

But, after taking a close look at the McDonald’s ingredients, he said he realized much of it was no different than what he kept in his own kitchen at Redbird.

With the exception of a dollop of sour cream used in the chilled avocado soup, every dish was created with ingredients used for a bevy of McDonald’s menu items: salads, McWraps, grilled chicken sandwiches, Egg McMuffins, Quarter Pounders and french fries.

“I made a concentrated effort to stay true to the challenge,” said Fraser, who was paid an undisclosed fee for his services.

Before the meal began, he said he was apprehensive, excited and nervous.

“I just hope no one hits me,” said Fraser, who recently appeared as a guest chef on Bravo’s “Top Chef.”

Halfway through the meal, he left the kitchen to update the group of McDonald’s officials watching the dining event on a television monitor. The officials, along with one reporter, were also eating Fraser’s courses.

He said nearly every plate came back “clean” to the kitchen. The only dish that many diners didn’t finish was the first course — a peppery avocado soup made with McDonald’s guacamole.

The second course, a salad topped with bacon bits and buttermilk dressing, was a surprising crowd pleaser.

Salmon and her guest, T.J. Valentino, said it was their favorite dish.

During the evening, and before the reveal, the diners were encouraged to upload photos to their various social media accounts using the hashtag #aTasteofSoCal.

Los Angeles blogger Vanessa Diaz also loved the buttermilk slathered greens. “This salad is #bacon-tastic! It’s probably the best #salad I’ve ever had,” she wrote on her “BriteAndBubbly” Instagram account.

Even Fraser, who saw her post while cooking in the kitchen, had to poke fun of her enthusiasm. “It might have been the first salad she’s ever had,” he said.

As the diners finished Fraser’s coffee custard dessert, he stepped back into the main dining room to announce the big reveal.

But someone had already guessed it by shouting, “Golden Arches.”

The reaction was mixed. Some jaws dropped. Some laughed. A few looked disturbed.

After the reveal, the salad-loving Diaz posted: “Holy What the What!!! #shocked.”

McDonald’s operator Scott Frisbie of Orange County, among the restaurant owners watching the live feed, approached the group with trepidation at the end of the night.

“I didn’t know what reaction I’d get,” he said.

But he said he got an enthusiastic and “warm” response. Many asked a lot of questions about upscale menu changes in Southern California, including the new line of Taste Crafted sandwiches made with premium ingredients such as guacamole, blue cheese spread, spicy buffalo sauce and applewood smoked bacon.

Later on, he and other McDonald’s operators mingled with curious food writers and photo-centric bloggers like Roshonda Payne. The lifestyle blogger said she had no idea she was eating McDonald’s food.

“It’s just goes to show you that McDonald’s is (real) food,” said Payne, whose lifestyle blog is called the The Savvy Sistah.

Chef Eric Crowley, a Los Angeles cooking instructor, said he enjoyed the tasting menu even though it was “homogeneous” and lacked a lot of bold flavors.

When he learned it was McDonald’s food, “it all made sense,” he said.

Fraser said he was particularly concerned about serving food to Crowley, who was taking meticulous notes throughout the event.

“I thought he was going to skewer me,” Fraser said.

But Crowley said he was not upset by the trickster fast food meal. He said he was excited that McDonald’s was trying to improve its image.

“If I went to McDonald’s and got food like this, I would go more often,” he said.

As for Fraser?

When the three-hour event was over, he said he was relieved.

Would he do it again?

Yes. But first thing’s first.

“I’m going to get a drink,” he said.

For the record, this story was updated Feb. 9: Representatives for Neal Fraser said the Los Angeles-based chef uses Jidori or Mary’s Free Range chickens at his restaurants. Because of incorrect information provided to the Register, the supplier was misstated in an earlier version of this story.

Contact the writer: nluna@ocregister.com and follow the Fast Food Maven on Twitter, Facebook and Instagram.