April 17, 2014 12:53 p.m. ET  ONE SHOULD HAVE an established policy when a strange new bottle of liquor arrives on one's doorstep. It is like a baby in a basket: Once you bring it into your house, you must watch over it as if it were your own. Work with it carefully and it will thrive, mature, charm your guests and keep you warm in old age. Allow it to mix with the wrong associates and you will end up the central figure in a farfetched melodrama.  My new guest is a bottle of Génépy des Alpes, which arrived on an otherwise innocent-looking sunny day. As with a baby, I first endeavored to ascertain its origins. Its papers proclaim Génépy des Alpes—which Google Translate helpfully informs me means "Génépy Alps"; isn't technology grand?—to be a "legendary alpine herbal liqueur," which startled me, because I was holding the legendary thing in my hands. Despite the liquor's French pedigree—they mix up the stuff in Chambéry using a hush-hush recipe—the marketing copy provided by one distributor sounds more Californian ("Efforts to brand this style of product have been nothing short of epic"—dude, really?), and the importer's serving suggestions are as flimsy as edelweiss. The liqueur is "very welcome after a fondue," the label says, but what isn't welcome after a fondue? "Serve immediately after very satisfying sex," it might as well say, "and enjoy."  I ushered the new arrival out of its things and took a good look at it. Génépy des Alpes is pale green, almost jaundicey, an alarming color for a baby but an alluring one in a shot glass. It has a light, crisp smell, much better than a baby, presumably due to the "petite and rare variety of artemisia" that the label tells me is "most prominent" in the taste. It reminded me of Chartreuse, the French liqueur pretentious people drink in novels and pretentious novelists serve to people, so I poured a dose of that into a shot glass and lined them up. They eyed each other like step-siblings. "We are all family," I told them. "My love for you, Chartreuse, will not diminish with this new arrival." The silence seemed companionable, which I thought was a good start, and so I tried Génépy des Alpes as a substitute for Chartreuse in a Last Word, a cocktail renowned in my household because a) it's weird, b) it's easy to make and c) it gets everyone knackered. I christened this variation the Yodeler, because it's an Alpine Last Word—get it?  ¾ ounce Génépy des Alpes  ¾ ounce Bluecoat (or similar solid but unshowy) gin  Stir and strain over ice into a glass from which everyone suddenly wants to sip.  In a Yodeler one needs a gin that acts as a wet nurse, nourishing its young charges without exposing itself overmuch. The results, according to a small group of grownups who suddenly gathered round, were quite lively. The Yodeler is less complex than the Last Word, but yodeling, in its way, is less complicated than talking. "You know what this reminds me of?" asked one of my comrades, who would not like to be identified but nevertheless is novelist Andrew Sean Greer. "That purple stuff you put in Aviations."  "Good call, Andrew Sean Greer," I answered, and quickly mixed up an Aviation with a splash of Génépy des Alpes instead of Crème de Violette, the ingredient that gives the Aviation a curiously 1980s purple hue—too much Crème de Violette and my household changes the name of the drink to the Prince and the Revolution. With Génépy des Alpes, however, we called it the Saint-Exupéry, after the author of "The Little Prince," who also flew reconnaissance missions with the French Air Force.  ¼ ounce maraschino liqueur, which you already have lying around from the Yodeler  Dash of Génépy des Alpes  Stir and serve to the other guests who have arrived just in time.  "Too strong," was the verdict, and it was true: The Génépy des Alpes was quite overwhelmed, as if the citrus was an overly boisterous family friend, causing our new adoptee to hide behind the curtains. "Come on out," I told the shivering liqueur. "Let me try you in a Martini."  Introducing a new bottle to unadorned gin is like introducing a stray child to the mistress of the household: If they don't get along, it's not gonna happen. Given Génépy des Alpes's softer, slightly citrusy bouquet, I chose a different gin, the United Kingdom's Sipsmith, which is A.S. Byatt to the American Bluecoat's Toni Morrison: fancier, more flowery and drives on the other side of the road. "Tastes like 'Possession,' " raved Mr. Greer after the first sip, and I'm almost positive he meant the celebrated novel and not a demon clutching an innocent soul.  1 ounce Génépy des Alpes  Stir and serve up with a peel from the desiccated lemon still hanging around after the Saint-Exupéry.  "Not bad," pronounced the only actual mother in my household, my charming wife, who birthed a child who surely someone remembered to pick up from elementary school. "But try it in a vodka Martini."  All babies who enter my household are instructed that there is no such thing as a vodka Martini, just as there is no such thing as a just war or a charming child who is awake at 9 p.m. Nonetheless I humored the lady of the house, and thought the adopted child's meek, fruity demeanor might mingle nicely with Core Vodka, which they distill in Valatie, N.Y., from local apples. Hmm, what to name the thing? What else is alpine and fruity?  1 ounce Génépy des Alpes  Strain into the waiting arms of my charming wife.  She did not cough while she sipped it, and when she passed it around the results were curiously vanilla, by which I mean not "sexually tame" but "actually tasting like vanilla." "I like vanilla," said my wife, unnecessarily exposing herself to ribald mockery, but thank goodness dinner was ready. I had seared some salmon with a gorgonzola crust, not quite fondue but as close as it gets in my house without scrounging around the basement for a long-ago wedding gift. Hastily, I poured a dose of Génépy des Alpes into several flutes and filled the rest with Champagne. Bubbly? French? My DVD player could name this drink itself.  ½ ounce Génépy des Alpes  Fill with Champagne or sparkling wine and serve to people who are already tipsy.  "Fruity!" exclaimed the novelist. "Flowery!" exclaimed the missus. Myself, I was putting the baby to bed. It had been a very busy evening for Génépy des Alpes, and it was all tuckered out. Tomorrow, we would try it in a sidecar (the Citroën?) and with white wine (the Kir Bourgie?), but for now, the bottle needed to go where all my guests end up sooner or later. In the liquor cabinet.  —Mr. Handler is the author of four novels, including, most recently, "Why We Broke Up," with illustrator Maira Kalman. As Lemony Snicket he has written the series "All The Wrong Questions" and "A Series of Unfortunate Events."
In a new monthly feature, we send a bottle of spirits to a writer who is tasked with getting to the bottom of it. This month, novelist Daniel Handler mixes cocktails with the herbal liqueur Génépy des Alpes.