As she bit into a spicy, aji amarillo-marinated Peruvian steak sandwich topped with Oaxacan cheese on a freshly baked bun at the new Mendocino Farms in Santa Monica, Melissa Delgado thought she’d found a new favorite spot.

The 23-year-old had no idea she was eating at a chain restaurant. And for a new breed of restaurant owners, that’s a great thing.

“I didn’t know there are a bunch of these,” she said after learning that there are a dozen Mendocino Farms throughout the area. “It feels like a cool, little single spot that I just found.”

But it’s not the only local place where customers could be forgiven for thinking they’ve just discovered a rare food gem. The L.A.-based chain is among a growing generation of restaurants that are redefining the idea of casual dining.

“I started to see this becoming more of a trend in the last five years,” said Andy Harris, executive producer and co-host of The SoCal Restaurant Show on KLAA (830 AM). “It feeds into the millennials and what they’re looking for.

“I think for the millennial, they’re looking for more of a personal experience, and they’re looking for a restaurant concept that has some heart and soul and local character,” he added. “The big chains for the most parts just don’t have that anymore.”

The big casual dining chains like Applebee’s and Chili’s, which have more than 1,000 locations nationally apiece, have the upper hand when it comes to numbers, name recognition and, ultimately, sales. But for the new group of smaller local spots, where menus can vary from gourmet sandwiches to comfort food, bigger isn’t always better.

Instead these new chains are driven by the demands of foodie culture, the desire for locally sourced food and the drive for a more authentic experience, both in the menu and the look of the restaurants.

“We thought we would do one or two of them,” said Mario Del Pero, who founded the Mendocino chain with his wife, Ellen Chen, in 2006 in an effort to combine high-volume business with high-end ingredients.

Some of the new generation of chains include the four Larder restaurants run by James Beard Award-winning chef Suzanne Goin and James Beard-nominee sommelier Caroline Styne. There are also Stout Burgers and Beer and Cerveteca, which serves elevated comfort food in its three locations.

“I would say some of these places are part of a new era of fast casual dining,” said Joshua Lurie, who has followed the local dining scene since 2005 with his blog Food GPS. “In places like L.A., where anything is possible with food, standard fast casual food just doesn’t cut it anymore,”

For Del Pero, whose chain stretches from the Westside and the San Fernando Valley to downtown L.A. and Orange County, the key to being a chain without feeling like a chain is in the sourcing of the food and avoiding a cookie-cutter look for his places. Del Pero said each restaurant is made to specifically fit the space and neighborhood rather than a repeated corporate design. To ensure this, he often hires different designers for each location.

“We really want each store to reflect the neighborhood,” he said.

The latest Mendocino opened in Santa Monica in November. Del Pero plans to continue his expansion with more locations in Northern California next year.

For Charles Lew, co-owner and founder of Stout Burgers and Beer, his mission is pairing and elevating two simple menu items that are almost universally loved.

“The concept was to take craft artisan beer and pair it with gourmet hamburgers,” Lew said as he sat inside his Santa Monica location, which includes a bar and a patio.

Dressed in a slim-cut dark suit and sporting a shaved head with a short-cropped beard, Lew seems more like a connoisseur of high-end spirits and fine dining than a typical burgers and beer guy. But Stout is no typical beer and burger joint.

“We said, let’s take an accessible food product, such as your hamburger, let’s take a huge growing market, your craft beer, and let’s elevate the two,” he explained. “The wholes are better than the parts.”

The restaurant employs a “beer guy” who travels nationally to breweries to source new brews, and the menu offers pairings to create tasty combinations.

“We’re actually going to pair it for you and tell you why these go together, and we’re going to try to create a real experience for you,” Lew said.

While Lew aims to transform burger and beers, the Larder restaurants, with the respected reputations of the James Beard Foundation-recognized owners, started out with a solid reputation for this small chain.

“These folks come with very impressive fine dining credentials, and they’re known for seeking out fresh and seasonal ingredients before it was a trend,” Harris said.

“And in the food world, you can’t do any better than when you’re recognized by the James Beard Foundation,” he added. “That’s the Oscar of the food world.”

The Larder began as a combination of casual cafe and marketplace at another of their restaurants, Tavern.

“We took the front room and styled it as a place you could come to any time of day to get pastries, salads, cookies, sandwiches — get something you can heat up for dinner later at home,” Styne said.

The Larder at Tavern opened in 2009 and has since been joined by The Larder at Maple Drive in 2010, The Larder at Burton Way in 2013 and The Larder at LAX in 2014.

“We don’t have hundreds of them; we have four,” Styne said. “Maybe we’ll open a couple of more in the future, but we don’t have such a large group that we’re taking something and cookie-cutting it and shoving into different types of spaces and making everything look the same.”

Next year, more people will become familiar with the Larder chain when two concession spots open at the Hollywood Bowl during the 2016 season.

Cerveteca, meanwhile, offers L.A.-influenced, feel-good food and stylishly rustic locations.

“I call it L.A. comfort food,” said Cerveteca owner Oscar Hermosillo. “It’s basically inspired by the food that we, as a family growing up here, ate. It’s not necessarily Mexican food, but definitely influenced by our background.”

That means tacos, pulled pork sandwiches and a burger called the La Puente Original.

“I grew up next to In-N-Out, and it was our neighborhood burger spot,” Hermosillo said. “I used to mimic their burger in my backyard, and so when I opened a restaurant I said, let’s make that backyard burger.”

The flagship Venice location opened in 2011 and is sourced by local farmers markets in Santa Monica, Venice and Mar Vista. There are also locations in Culver City and downtown L.A. Hermosillo also owns two other restaurants, Clutch and Venice Beach Wines.

On the weekends at the Venice Cerveteca, Hermosillo’s father works the bar while his mother helps out in the kitchen and chats up the customers.

“I love Mom,” said Concha Duenas, a regular at Cerveteca. “I call her Mom, too. I love her; she’s awesome. It’s like eating with family. Everybody here now knows me.”

Hermosillo’s not sure if there will be another Cerveteca; he says the future of his chain depends more on what feels right rather than just getting bigger.

“I’m always looking,” Hermosillo said. “If a neighborhood speaks to one of my concepts, I’ll do it.”