Serious enough, in fact, to base his business on the quality of the breakfast treat.
"I've made thousands of cinnamon rolls and really messed around with variations and ratios," he said. "The only way to get a cinnamon roll to this level of mastery, with filling, with dough, comes through experience."
Mirabal and his wife and fellow chef, Erin, are in the process of opening Brown Bag Bakery at 1901 W. Aztec Blvd. The location is the former home of Oliver's Restaurant.
The bakery is in the process of what is known in the restaurant industry as a "soft opening." It's open to customers, but Mirabal is still experimenting with some aspects of the restaurant.
James and Erin, both age 33, are veterans of the food industry. They met in 2003 at the Courtyard by Marriott, where he was the banquet chef and she was catering manager. They married a few months later and now have five children, ages 2 to 7.
James spent the last few years selling his rolls at farmers markets in Farmington, Aztec and Bloomfield, and picking up work as a caterer and personal chef. Erin handles the cupcakes and pastries.
James said he was "being spread pretty thin at one point" balancing the catering and other responsibilities. He and Erin were considering moving out of state for a fresh start when the Oliver's Restaurant space came open. They jumped at the chance to focus on a restaurant.
"As a resident of Aztec, seeing the place unoccupied and just collecting cobwebs wasn't right," he said.
The first iteration of Oliver's Restaurant, owned by Barbara Ellis, closed in June 2011. It reopened in May 2012 under the management of Juan Leon. It closed again shortly thereafter, and had been vacant.
Ellis still owns the building. Mirabal and his wife are running Brown Bag Bakery with the help of a silent backer.
James grew up in Las Cruces and graduated from the California School of Culinary Arts in Pasadena, Calif. He moved around the country before coming in 2003 to San Juan County, where his parents lived until recently.
The restaurant has 11 employees, and Mirabal said he's happy to have the kitchen help. "It's nice being able to depend on people back there so I can focus on the customers," he said.
The location is convenient to the large San Juan County government and judicial complexes across the street. Mirabal also plans to be open early to catch oil and gas workers in the morning. In December, the bakery is open 6 a.m.-4 p.m. Mirabal plans to expand the hours if necessary.
"We can have hot, fresh cinnamon rolls at 6 a.m. or maybe a quiche if they wanted to mix things up," he said.
Aztec leaders couldn't be reached for comment about the business, but the town may be hungry for it. A Facebook post about the new bakery Wednesday quickly attracted enthusiastic comments and "likes" from Aztec locals.
James wants to open a tea room and purchase an espresso machine early next year. He serves Allegro Coffee, a roaster in the Denver area.
James describes himself as a "missionary" for flavorful food. He speaks of his cinnamon rolls with the passion of a believer.
"They're crispy on the outside, and they're pull-apart soft in the center," he said.