“Darn Good!,” a peanut butter, caramel and chocolate cookie studded with crumbled chunks of Snickers and Baby Ruth is “chewy.” The “Black Russian,” dark chocolate blended with Kahlua, is “intoxicating” and “Geisha Seduction,” rich dark chocolate dotted with crystallized ginger is “seduction.” These are more than just evocative descriptors. What you read is what you taste and feel. And that’s the whole point.

Heather Sue Mercer categorizes her gourmet chocolate chunk cookies by sensation, texture, and season “because it’s fun and it makes sense.” “Ruby et Violette,” her tiny jewel box of a café is nestled in New York City’s Hell’s Kitchen neighborhood. Originally settled by the Irish and best known as the setting for “West Side Story,” it’s adjacent to the city’s theater district and is a treasure-trove of idiosyncratic family restaurants and bohemian cafes. The unconventional Mercer sisters, Ruby et Violette’s owners, fit right in.

Jenji, the oldest, doubled-majored at Stanford, has a Masters from the University of Chicago and a J.D. from Georgetown, while Bekah, a mother of three, also double-majored at Stanford and has a graduate degree in mathematics. But the café’s driving force, strawberry blonde, 5’10” Heather Sue, is the black sheep of the group, having earned only a single bachelor’s degree. The self-proclaimed jock “since birth” and former financial trader also plays professional poker. Taking over Ruby et Violette was her idea.

“It was our favorite place for cookies,” she says emphatically. “We’d get them for parties, weddings, christenings. We’d make up reasons to get them. Then one night, I’m playing poker at the Borgata and I get a call that Ruby et Violette is closing,” Heather Sue remembers. She was devastated…for about a minute. Then she decided to buy it. She called her sisters from the Borgata saying, “We’re going to buy a bakery.”

“I’m a total sugarholic and I searched New York for the best cookies, pastries, chocolates, candies, whatever,” Heather Sue says. “I can tell you who makes the best cupcake, the best éclair. It’s my thing. I’m obsessive about the best.” Jenji and Bekah had their doubts.

“Okay, I originally studied biomedical mechanical engineering - prosthetic limbs. I dabbled in Art History and have a degree in Economics and Management. Nothing here screams ‘cookie.’ I get it.” But Jenji and Beckah knew that while their sister had the family drive and discipline in spades, at that point in her life she “needed a focus.” So they helped her mop, sweep, scrub, lug and bake.

Heather Sue decided to update cookies, create new ones, open a café, and find a professional baking space. In overhauling Ruby et Violette, she essentially created an entirely new business. Eighteen-hour workdays stretched into weeks, months and years. She moved the baking off-premise, gutting the original store which was “so small and cramped it looked like a palm reader’s shop” and turning it into neo-Edwardian homage to “My Fair Lady’s” black and white Ascot scene. “Everything you see was a decision, from flooring to sinks to hardware to brewing machines to décor to contractors.”

Heather Sue wanted to modernize or retire some of the original flavors like Jenji’s favorite, ‘Orange Blossom,’ an orange-cardamom cookie. “She has the sophisticated palate and to this day I need her input. But I wanted to add flavors that a child would be excited about.” With the cafe shaping up she turned her attention to cookies. Obsessed with the best, she hired the best, Florian Bellanger.

Bellanger, former American executive pastry chef of luxury patisserie Fauchon and colleague of pastry superstar Pierre Hermé, had also been at New York’s four-star “Le Bernadin.” His pastries were works of art. Her culinary background didn’t exist. The hard-charging, plainspoken, all-American jock and the soft-spoken, easy-going, creative French genius turned out to be a match made in cookie heaven.

Heather Sue created a cookie that captured the essence of children’s favorite sweets called “Candy Jar,” a chocolate chunk cookie flecked with Snickers, Oreos, Reese’s Pieces, Toffee and Butterfingers. For fancier palates, “Kir Royale” balances blackcurrants with champagne and creamy white chocolate chunks. “Mom ‘n’ Pop Toffee” blends dark chocolate chunks and buttery toffee with a hint of sea salt. And “Bananas Foster” mixes caramelized, flambéed bananas with semi-sweet chocolate.

Since most of their cookies are shipped, Heather wanted packaging that reflected the brand’s new vibe. She found elegant cigar-type boxes tied with satin ribbon and lined them with a soft gold insert to hold cookies. That meant each cookie had to be the same size to fit into the insert. A huge headache.

Recipes determine flavor, and altering them to change the cookie’s “spread” changed the taste. Not good. The solution: hand-weighing and hand-dropping each cookie. It was the only way to make them uniform. “Our bake time is so specific. If the weight or bake time is off, the cookie won’t fit the insert,” Heather Sue explains. Individual weights and times are assigned to each of the more than 100 cookies.

Ruby et Violette’s signature holiday gift box featuring Crème de Menthe, Champagne Strawberry, Rum Raisin, Red Velvet, Egg Nog and Gingerbread is a nod to Christmases at the Mercer’s. “It was the only time of year Mama let sweets in the house, decorating with bowls of Hershey kisses and M & Ms. Each window of the Advent calendar had candy.” They didn’t do traditional sugar cookies. They baked Snickerdoodles, Russian teacakes and peanut butter thumbprint cookies with kisses at the center.

Heather Sue’s favorites were the family gingerbread houses. “As a kid I was always in complete awe over the scenes my parents created. They were always so clever and fun and beautiful and as I got older I wanted to create something just as incredible.” Maybe she was meant to own a cookie café after all.

Click here for Ruby Et Violette's Pumpkin Chocolate Chunk Cookie recipe