So far this winter, a farm in Placerville (El Dorado County) has found 1 pound of prized, elusive black truffles, leading to its first sale to a Northern California restaurant on New Year’s Eve. Around the same time, a 10-year-old Santa Rosa orchard also found its first truffle. Meanwhile, a nearby Santa Rosa orchard owned by Jackson Family Wines has unearthed an astonishing 25 pounds of truffles this season, some of which are being served in San Francisco restaurants like Saison, Birdsong and Che Fico.

About a decade ago, California-grown black or Périgord truffles were at best a dream, and at worst a long shot. That’s when about a dozen farmers started planting orchards of hazelnut and oak trees, their roots inoculated with Tuber melanosporum spores. If the orchard was carefully tended, the first black truffles could form within five to eight years, though it would take a couple more years for an orchard to really bear fruit.

It’s happening: For the first time, California has a truffle season, which goes from December into March, as growers are making serious progress toward creating a viable locally grown version of the European luxury ingredient.

“You could almost smell the earth coming off them,” says Micah Malcolm of Taste Restaurant and Wine Bar in Plymouth (Amador County), who shaved farmer Staci O’Toole’s Placerville black truffles over mushroom ravioli for a $120 New Year’s Eve menu, and was willing to spend an extra $15 per ounce over the price of imported truffles. “It’s the earthy, sweet smell that is very captivating. Shaving it over something warm makes the oils break down. You could just smell it in the whole restaurant.”

Although there are other parts of the country where various types of truffles are grown, California is seen as being closest in climate to their native Southern Europe. But uncertainty remains. When a dog found the first truffle at the 10-year-old Santa Rosa orchard of Harshal Sanghavi and Matt Hicks in December, they immediately sent off the walnut-size tuber for DNA testing, which confirmed it was a Tuber melanosporum — and not another random variety that sometimes crops up.

“It was very exciting,” says Sanghavi, who has overseen years of intensive pruning, irrigation and re-inoculating of the trees at their orchard. “We were looking for some kind of sign that we were doing the right thing.”

Staci O’Toole first visited the Placerville truffle orchard in 2016, when it was overgrown and neglected after being planted more than a decade before. She brought along her Lagotto Romagnolo, Mila, an Italian truffle-hunting breed with tightly curled mops of fur — as cute as a Muppet and as serious as a foxhound.

The pair were on-site for an hour when one of the property owners pointed over to Mila, who was digging a hole and then marking her find with a head shake, just as O’Toole had trained her. O’Toole remembers kneeling down and carefully moving back the dirt, then sticking her own nose in the ground.

Mila had found their first Northern California truffle.

“I was so excited I started crying,” says O’Toole, who had been training Mila as a hobby. The 2016 find was so thrilling — and prophetically, just 5 miles away from the first discovery of gold in California — that O’Toole eventually convinced her husband to purchase the property as a truffle tourism project. She has spent the last few years rehabilitating the orchard on weekends, and they moved there permanently in December.

Last week, culinary gardener Tucker Taylor brought one of the Jackson Family Wines truffles into the city to see if any of his chef contacts were interested in buying. Although truffles were first harvested at the winery two years ago, this is the first season they have extra to sell.

Taylor, who made his name in the French Laundry garden and now runs the culinary gardens on Jackson Family Wines properties, says chefs find the aroma on par with black truffles imported from Europe: “The chefs say the taste is between a summer truffle and a black Périgord,” he says, referring to the slightly less expensive and more chocolatey summer black truffle (Tuber aestivum). “I think it’s the type of soil.”

Rather than the usual round nugget shape, one of the larger truffles was about 3 inches wide with multiple growths like camel humps. The aroma was of damp earth and funk but also Parmesan, dried tomato and pineapple. The lighter fruity and floral notes, which are more apparent in very fresh truffles, created an experience that you can imagine leads to impulsive real estate purchases.

When Taylor brought truffles to Chris Bleidorn, chef at Birdsong, in the last week of December, Bleidorn told him he hadn’t planned to serve imported truffles at the restaurant. Having a local source changed that; Bleidorn used them in his New Year’s Eve menu and told Taylor he hopes to order more when the orchard’s production increases.

Most diners will be struck by the immediate scent of a truffle shaved onto something warm; once cooled, say, on a slice of pizza, a sliver of truffle doesn’t hold much flavor.

“You’re putting shavings on your dish that are just warmed and excited by some warm fat around it. So a lot of the experience is the aromatic part of eating,” says Ed Roehr, chef-owner of Magpie restaurant in Sacramento, who recently visited O’Toole’s orchard to watch Mila find a truffle. He describes the aroma as an oil-cured black olive moving toward dried cranberry, with a hint of earthiness.

Even though Roehr considers Magpie an Italian restaurant of sorts, he doesn’t use imported truffles because he sticks to ingredients from the Central Valley and California. For that reason, he is excited about O’Toole’s endeavor.

Fran Angerer of Alexander Valley Truffle Co. counts about 10 known truffle orchards in California that haven’t yet produced truffles, from San Luis Obispo to Willits (Mendocino County), including his own in Geyserville. He would love someone from UC Davis to take an interest and help California growers figure out the right growing methods.

In the meantime, he says, he and several other local growers share tips.“It’s always been a very secretive business,” says Angerer, who has plans to plant another orchard in Healdsburg. “We’re trying to open it up.”

Now that the Jackson Family Wines orchard is reaching maturity, the next step is to train the truffle dogs to not just find any truffle but to recognize when they are at the proper state of ripeness for digging up, says orchard manager Brian Malone.

While her business is still at its beginnings, O’Toole envisions having a truffle tasting room and farm stays. She has embraced her truffle life, starting her day by walking her dogs through the orchard with her coffee, still in her pajamas.

By the time she gets back, she says, “My nose is as dirty as theirs because I’m sniffing around in the holes. My pajama pants are stained on the knees.”

But with more truffles comes more responsibility, like a better infrastructure for selling them. “When you just get a few truffles each time you go hunting, it’s super easy to find a home for them,” Malone says. “When you start harvesting pounds at a time, you have to formulate a plan ahead of time.”

Tara Duggan is a San Francisco Chronicle staff writer. Email: tduggan@sfchronicle.com Twitter: @taraduggan