The brothers sat across from each other at a casino restaurant, having the kind of heart-to-heart unique to the bleary hours of Las Vegas nights.

It was June 2010, and Aaron Pool had graduated from the W.P. Carey School of Business at Arizona State University a year before. He was living at a rental house his parents owned while trying to open a restaurant, an effort that really just looked like hanging out a lot, with some business cards.

Pool’s older brother, Jared, a San Francisco dentist, told Aaron he had taken enough help from his parents. It was past time to get a job. He should put the restaurant thing off until he had some savings.

Pool was devastated. He thought his older brother was his biggest supporter. Back in Phoenix, Pool told their mom what had happened and broke down. He had no culinary experience, no loans, no potential locations and only two recipes he felt good about, one for tomatillo chicken and one for salsa.

“God, crying in the front yard, at your mom, that’s kind of a low point,” Pool said.

Four years later, with its assembly line featuring 25 enchilada filling and topping options, Gadzooks Enchiladas & Soup is thriving, with customers often arriving 45 minutes before opening. The concept embodies how post-recession America dines out: fast-casual and aimed at Millennials, according to the NPD Group study “The Future of Eating,” released this week.

Though fast-casual spots like Panera Bread, Chipotle and Phoenix-based Fire’d Pie make up only 1.6 percent of the nation’s 990,000 restaurants, they lead the industry’s growth. Pool estimates the Valley could support 20 Gadzooks locations.

Fast-casual visits in 2013 were up 8 percent over the prior year, while the total restaurant industry remained essentially flat, according to the NPD Group, a Rosemont, Ill., market-research company. Spending at fast-casual restaurants, which specialize in things such asbetter burgers, healthful Indian dishes and gourmet salads, increased by 10 percent last year, while it increased only 2 percent industrywide.

“The driving force behind this are Millennials,” said Julia Gallo-Torres of the international consumer research company Mintel. “They’re younger, they don’t make as much money, but they eat out more than any other group. They’re not really interested in big, elaborate meals.”

With roughly 77 million members ages 18 through 34, the Millennial generation is so massive and racially diverse that it is almost impossible to generalize about, according to a March Pew Research Center report. But there are stereotypes about those who were born after 1980, the generation’s cut-off date. At 26, Pool lives up to many of them.

He has a sense that he’s special. He’s achievement-oriented, with perfectionist tendencies and high expectations. He’s comfortable talking about his personality as a business asset.

These traits are the reasons “almost everyone” who heard about Gadzooks told Pool he would fail. They’re also the reasons he recently celebrated Gadzooks’ first anniversary.

Super self-confident

Pool is so self-confident that he believed he could open a restaurant even though he’d never worked in one.

At ASU, Pool and his friends ate out often, and he wanted to open the kind of restaurant he frequented.

He wanted a place with higher-quality, fresher ingredients than at fast-food restaurants, and served more quickly and cheaply than at full-service restaurants. A place that offered infinite customization, with ingredients in any combination and amount, prepped and cooked in about five minutes or less.

Pool’s preferences are in line with his generation’s. Customization, speed and variety are key considerations when Millennials choose where to eat, according to Mintel Menu Insights.

Millennials represent $200 billion in potential spending, a number that will grow as they mature in their careers and make more money, according to Nielsen, the global consumer-information and viewing-measurement company. They influence every kind of restaurant, even those once marketed to their parents and grandparents, according to Mintel Menu Insights.

Olive Garden, Applebee’s, TGI Fridays and Chili’s all have shareable, small-plate, mix-and-match menu items aimed at 20- and 30-somethings.. Even the Paradise Valley resort restaurant Lon’s at the Hermosa now has slider-size burgers and half-size salads on the bar menu to draw young professionals for happy hour.

But what those restaurants accomplished through market research, Pool achieved through intuition and chutzpah. He said some of his confidence, which won over the loan officers at Pinnacle Bank, where he got a U.S. Small Business Administration loan, came from his parents, Linda and Craig.

Linda said they raised their children to see themselves as capable, resourceful and, yes, special.

“We really thought he had a great idea,” Linda said. “I wanted to make sure all my children went after what they want. I told him not to wait; he’s single, he’s young, he has no commitments. Now is the time.”

Five years before that night at the Las Vegas casino, in 2005, Linda made a chicken, spinach and mushroom enchilada casserole from her own recipe on a family vacation. Right then, Pool decided to open an enchilada restaurant that would serve the kind of food his family made.

“It’s really a light bulb over your head, and you always do some research and find out that it’s been done a million times,” Pool said about his idea. “But this hasn’t.”

Pool wants all menu items to be memorable and bold, even the mashed potatoes, which, with garlic, green onions, and cotija and asadero cheeses, are, well, bold. That’s why there’s Modelo-braised bison. And his family’s tomatillo chicken. And creamy-tasting tortillas made from fresh masa. And jalapeño-dotted cornbread based on the recipe Linda has been serving every Thanksgiving since he was in preschool.

These aggressive flavors are a good fit for the nation’s increasingly adventurous palates. For about three years, such publications as Food Business News and QSR, a publication for fast-food and fast-casual restaurants, have published stories advising food-service executives to offer more “ethnic,” “unexpected” and “international” flavors.

A do-it-yourself MBA

Aaron Pool has no interest in working for someone else or working his way up.

“I always thought I could make better decisions than our outcomes in group work or doing other projects in college,” Pool said. “I hope I don’t come across as egotistical, but I am confident in my taste in design and in what is quality, and what is good work and what is bad work.”

This meant that while developing Gadzooks’ recipes, figuring out how to configure the kitchen, deciding what kind of oven to buy and mapping out his business plan, Pool didn’t use cookbooks, handbooks or any of the research tools one might typically turn to while making such expensive decisions.

He saw opening a restaurant as a practical MBA, a crash-course in everything he would need to know. Today, he describes that notion as naive.

In his mom’s central Phoenix kitchen, Pool spent hours and hours not actually braising, but destroying various cuts of meats. It took him a year to go from fork-resistant to fork-tender. When he was figuring out his verde and habanero salsas, he bought bag after bag of chiles, roasting some, leaving others raw, blending some, chopping others, developing each recipe through trial and error.

“I didn’t even let friends try my food until a few weeks before opening,” Pool said. “It was never good enough. I knew what I wanted things to taste like, and I wanted to do it on my own.”

And when the contractors asked him where to put the drains, where the fryer should go and other logistical questions, Pool “faked it until I made it. For months.”

And when his oven arrived, Pool ruined the first several cuts of meat he put into it. All of his recipes had been developed in his mom’s conventional oven. But he needed a convection oven to heat the enchiladas super-fast so they could be served by the time the customer was ready to pay.

All of his recipes had to be reworked, something he now describes as “duh, so stupid.”

“I don’t like calling people and asking for help,” Pool said, wincing.

He is, however, calling commercial real-estate agents.

Pool is looking to open his next locations.