Chef Ryan McCaskey of Acadia was staging at Trio in Evanston, Illinois—where Alinea chef Grant Achatz then helmed the kitchen—when he first encountered the butter from Animal Farm , a small creamery based in Orwell, Vermont.

“This butter was amazing and the most vibrant gold,” he remembers. More than 10 years later, McCaskey was intent on offering the butter at his own Chicago Michelin-starred restaurant…if he could.

Photo by Anthony Tahlier

“I called their farm a couple of years ago, but they didn’t have enough,” he recalls, likening his pursuit to the quest for Elysian Farms lamb , another covetable ingredient for chefs nationwide due to the farm’s small production and highest quality standards. “You kind of have to have a chef’s blessing in order to acquire it.”

Soon enough, though, McCaskey’s luck changed. As of last year, he joined the ranks of Thomas Keller, Barbara Lynch, and Patrick O’Connell as one of the four chefs in the country to carry the choice product. For Animal Farm founder Diane St. Clair, the chef selection process is rooted in the potential of the partnership more than anything else.

“I choose to work with chefs with whom I can form ongoing relationships,” says St. Clair, who has worked with Keller for more than 16 years. “These are chefs who seek out the finest ingredients and who appreciate the labor and care that goes into making these products.”

Photo by Animal Farm

For St. Clair, that labor entails making butter by hand in small batches with cream from just 10 cows. It’s a number she purposefully keeps small for her farmstead dairy, which is a dairy that sources its cream entirely from its own herd.

“Making a farmstead product gives you the opportunity to control your raw materials, which are influenced by everything from what the cows are eating to the amount of stress they encounter,” she says. “Unlike cheese, butter is directly correlated to the quality of the cream—there’s not a lot of fooling around you can do to make the product good if the material you’re working with isn’t of the highest quality.”

Vermont Creamery founder Allison Hooper, whose company sells upwards of 675,000 pounds of butter annually, agrees.

“I think that butter is a product that accentuates the difference in terroir because it’s a very simple art,” she says. “There isn’t a lot of nuance in making butter, so you’re really relying on the raw materials to develop flavor.”

Photo by Betsy Thompson

After spending time making butter from Jersey cows on a dairy farm in Brittany, France, Hooper relocated to Vermont and began sourcing cream the next best way she could: from a local dairy co-op.

Though “terroir” as a term is well referenced in the wine world, it’s not as widely practiced when it comes to gastronomy. Still, it doesn’t mean the same principles don’t apply — especially when it comes to dairy. “Just as great wine is usually from one vineyard and great olive oil is from one farm, I believe dairy should be treated the same,” says chef Stephen Harris of the Sportsman in Seasalter, England.

Hooper concurs. “Terroir to me means, ‘what are the resources you have around you to make something—what is your milk supply, and what is your savoir-faire—meaning, do you know how to use what you’ve been given?'” she says.

Hooper is hard-pressed to find many commonalities between her butter today and the kind she made in Brittany—after all, she was working with raw milk back then—which makes a strong case for the beauty of terroir.

“I think that if you were to take our butter and taste it next to Irish butter or Danish butter or French butter, they would all be wonderful and different,” she notes.

Chef Barry FitzGerald, who oversees Bastible restaurant in Dublin, might be just a little biased. There, he’s churning his own butter with cream that he sources from an organic farm in Wicklow, a 45-minute drive from the restaurant. Though the cream is coming from a single-estate dairy farm, variation is hardly out of the picture. The butter’s flavor changes with the seasons—right now, it’s floral, which FitzGerald attributes to the abundance of wild herbs and flowers brought on by the season’s increased rainfall.

“I think Irish dairy products are definitely some of the best in the world,” he says. “We have such green pastures, and, therefore, amazing butter, milk, and cheese — we’re lucky here.”

St. Clair sees a drastic shift in her butter’s taste profile at the start of every season, as well, but the passing of time brings its own benefits.

“In the winter when my cows are on dried hay, their butterfat goes way up because there’s less water in hay than in grass,” she explains. Because Animal Farm already uses Jersey cows, a breed known for its exceptionally high butterfat content, you can expect flavor to skyrocket in hibernating months. Still, there’s no shortage of perks in the late summer. It’s then that Animal Farm’s pastures are legume-heavy, resulting in cream that is richer and deeper in hue.

Photo by Anthony Tahlier

“Everybody loves it in the summer because it’s such an amazing color — it looks like dandelion gold,” she says. “You could say ‘well, big deal,’ but a lot of the way we perceive taste has to do with the way things look. That yellow is many times people’s ideal image of butter.”

And ideal images are everything in the restaurant world, especially when you’re dealing with first impressions.

“We want our butter to make an impact—it’s one of the first things the guest eats when they arrive,” says FitzGerald.

Lingering impressions, according to McCaskey, may be just as important. “To this day, I can recall that my grandparents had bread and butter with dinner every night,” he says. “Warm, soft bread with rich, fatty butter is part of a whole standard of excellence—and one of the best things in life.”