“Turn your spoon upside down,” Siggi Hilmarsson, the beanpole-thin, ponytailed founder of the grandly named Icelandic Milk and Skyr Corporation, said as we sat in his small, cluttered office on West 26th Street on a recent afternoon.

In my spoon was a large dollop of pomegranate and passion fruit skyr, one of the four flavors (plus plain) of Siggi’s nonfat, strained yogurt that, in the tradition of his homeland, is exceedingly thick. In Icelandic, Siggi told me, skyr means strained or thickened yogurt. It’s the result, he explained, of using up to three times as much skim milk as is used in domestic yogurt. Still, I was hesitant to turn the spoon over. Having spent a lifetime spilling food on my clothes accidentally, why do it on purpose?

“Don’t worry; just do it,” Mr. Hilmarsson said. And so I flipped the spoon over. The skyr remained firmly attached to the bottom — now roof — of the spoon. Later, when I tried the same thing with Weight Watchers nonfat yogurt, the physics of the thinner yogurt made it go splat — luckily, this time, over my sink.

Barely three years after Mr. Hilmarsson — who was homesick for the breakfast staple of his Reykjavik childhood — began experimenting with skyr-making in the kitchen of his TriBeCa apartment, the squat, simply designed containers of his product have already earned pride of play on elite retail dairy shelves (at $3.25, it sells for triple the price of mass-market brands), including those of Murray’s Cheese, Bouley Bakery, and Brooklyn’s Stinky Cheese. And two months ago, Siggi’s skyr had its debut at 90 Whole Foods stores on the East Coast and in the Midwest. Lucky for Mr. Hilmarsson, American consumers have been receptive to new styles of yogurt, including a thick, Greek-style variety that has become a sensation here in recent years. The company’s ultimate coup happened when the skyr found its way into parfaits made at Thomas Keller’s restaurant, Per Se (Mr. Hilmarsson won’t comment on its inclusion, however). Arriving in New York in 2002 to attend Columbia Business School, Mr. Hilmarsson, now 31, had “no firm ambitions other than maybe doing something in the media world,” he said. As a newly minted MBA, he got a Wall Street job that didn’t thrill him. And the domestic yogurts with which he tried to replace the skyr of his boyhood didn’t impress him, either.

For starters, he found the texture of domestic yogurt to be too gelatinous, due to additives. “They’d become this smooth paste instead of curdy yogurt,” he said. Even more objectionable was their sweetness: “If you do want more sugar, it’s easier to add in than take out. Like, my mom would sprinkle a little brown sugar on my skyr,” Mr. Hilmarsson said. While Siggi’s plain skyr is free of added sweetener, a smidgen goes into fruit flavors including blueberry, and orange and ginger. For that, he uses agave nectar, a natural sweetener that has a low glycemic index, meaning that the sweetener enters the bloodstream more slowly than refined sugar. Caution: Sugar-seeking palates may not immediately take to the more modest sweetness of Siggi’s sykr.

In contrast to the labels on typical commercial yogurts, which feature a welter of additives, Siggi’s seem stark. That container of Weight Watchers Black Cherry nonfat yogurt that I found in the back of my refrigerator, for example, lists 21 ingredients, including crystalline fructose, inulin fiber, sucralose, whey protein, kosher gelatin, modified food starch, and red 40 and blue 1. By contrast, Siggi’s blueberry skyr lists just five ingredients: skim milk, agave nectar, blueberries, live active cultures, and vegetable rennet. Its 10 grams of sugar in a 6-ounce container is two fewer than what is found in the same size Weight Watchers container.

Using a 1913 recipe for skyr that his mother found in her local library, Mr. Hilmarsson began experimenting in his kitchen in early 2005. An attempt to make a honey raisin skyr failed. “The raisins sucked the moisture back in; they wanted to be grapes all over again,” he said. Later that year, he debuted his skyr on Saturdays at a local health food market. A friend who worked at Murray’s Cheese took samples to a staff tasting, and the skyr soon went on sale there. “That was a great endorsement for me — and I thought that maybe I could make a real business of it,” Mr. Hilmarsson said. At an upstate research dairy plant, he “scaled up” his yogurt-making skills. With borrowed funds, he set up a skyr facility in the dairy farming country of Chenango County, about three hours northwest of the city. Milk for the product comes from five local farms, none of which feed their cows growth hormones. “I know this sounds silly, but if the cows are treated better, the product tastes better,” he said.

Because of its thickness, Mr. Hilmarsson says his skyr makes great fruit smoothies, especially strawberry. “Let me know if you find any interesting uses,” he said. I had in mind something savory and seasonal. In Riverside Park, I harvested a bunch of wild spring scallions that had just popped up. After chopping them fine and washing them thoroughly — my wife worries about any dogs that may have walked in the park — I mixed the scallions with a half-cup of cauliflower florets that had been browned in a touch of olive oil, and two-thirds of a container of Siggi’s plain skyr. The result was silky, crunchy, and zingy. Come summer, this combo is sure to become a personal lunchtime staple. If only I knew what to call it. Maybe Siggi can think of a name in Icelandic.