It’s Friday night after a week of cold, icy weather, and patrons at the Third Rail are ready for an evening out.

The club is part of Harvest Hall, an entertainment-food hall concept adjacent to the Hotel Vin in Grapevine. Open since last February, Harvest Hall has been a draw for both hotel guests and locals. The spacious food hall, with a distinct design channeling a train station, features a bar plus multiple dining options. The Third Rail offers seating, a stage for live entertainment and its own bar.

Maria Huntley, the Third Rail’s popular mixologist, arrives about an hour and a half before her shift. Her silver hair is braided neatly into pigtails, and she jazzes up her uniform with a colorful floral tie, turquoise jewelry and several pins, including one that bears the image of a cocktail and the words “Call Me Old Fashioned.”

She preps for the night by cutting up fruit for garnish and setting up her mise en place: cocktail shakers, mixing spoons, bottles of bitters. Harvest Hall diners wander in and out of the Third Rail to dine or grab a good table for the evening’s entertainment. At 5 p.m., they order the first drinks of the evening.

We’re here for one of Maria’s Old Fashioneds, having been tipped off to its tastiness a couple of months ago during a conversation with some locals at a Grapevine restaurant. When talk turned to favorite cocktails, Maria’s name and Third Rail were brought up as a go-to for craft cocktails.

We take a seat at the bar, and she smiles and asks, “What are you having this evening?”

After a lengthy career as a nurse and mom, Maria Huntley, 62, decided to make a radical career switch at the age of 47.

“I was divorced and wanted to do something different,” says the longtime Grapevine resident, who admits she’s not much of a drinker. “I’m a little older than a lot of bartenders I’ve worked with, but with age comes wisdom.”

She got a job at a local restaurant where she watched how pears were muddled and fruit infusions were made and learned other tricks of the trade. A lightbulb went off, and she realized that a good cocktail depends on the proper balance of ingredients.

Maria bought bartending books, learned the history of Prohibition-era cocktails such as the Vesper and Sidecar, studied and experimented. At another restaurant, she learned how a single large ice cube affected drinks and even bought her own silicone molds to make them.

“At Third Rail, we go through so many of the big cubes of ice that they now buy them pre-made in bulk.”

We sample both a classic bourbon Old Fashioned and her spin on an Irish Coffee made with Jameson whiskey, coffee simple syrup, Xocolatl Mole bitters and a topping of whipped cream made with demerara sugar and coffee.

Both are smooth sippers, with the coffee version perfect for an after-dinner cocktail as the cream gives it just a hint of sweetness.

Maria welcomes the fact that more people are embracing mezcal and tequila, and created the Third Rail’s Agave Old Fashioned, which uses both spirits. The bar menu also includes a mezcal martini and the Salty Chihuahua, made with tequila and grapefruit juice.

Seasonal cocktails include a Trader Vic’s Mai Tai and the Sakura, made with cherry vodka, unfiltered Nigori sake and cranberry and peach juices. Not too sweet and a beautiful shade of pink, it’s perfect for warm weather.

As Maria makes a cocktail, she uses the handle of her bar spoon to mix the drink and then to create a perfect twist of citrus peel for a garnish. “I’m very precise with directions and measurements; the jigger is my best friend behind the bar.”

But she’s also quick to make eye contact and, always, smile. Attendees of her increasingly popular monthly classes at Third Rail, “Mixology with Maria,” include a group of men and women who have nicknamed themselves “Maria’s Magnificent Seven.”

“It’s a show behind the bar, but I’m here to cultivate relationships with our customers, too.”