I’m on my knees in a damp woodland, hands in the dirt. Scraping away at the soil beneath a tree, I feel something between my fingers. I rub the dirt off—but it’s not what I’m looking for. It’s not a truffle.

My guide, a Labrador named Gucci, is brought back to check the area. She buries her nose into the earth, tail wagging excitedly. There’s surely one in there... maybe a bit deeper? Gucci’s handler gently pulls her away, and I get back to work, carefully sifting the soil.

I was on an organized hunt as part of the annual Oregon Truffle Festival that takes place in January and February in Eugene and Yamhill. Truffles are similar to mushrooms, except they grow underground and are extremely pungent. Considered a culinary delicacy, they’re also very expensive. Certain Italian truffles can sell for thousands of dollars, even tens of thousands—precisely because they’re so darn difficult to find. (They also require careful handling and transportation.)

Oregon is blessed with four types of wild truffle—Oregon winter and spring white truffles, and the Oregon black and brown—which can be harvested pretty much all year round. They tend to exhibit more floral and herbal characteristics than their European cousins. They also tend to be a lot cheaper.

Truffles are the spore-bearing, fleshy “fruit” of a fungus. They grow on the roots of trees in a mutually beneficial arrangement called mycorrhizae: The fungus receives sugars from the host while passing on nutrients from soil to the tree. They’re the ultimate friends with benefits.

In Oregon, truffles are found around Douglas firs. “They’re everywhere, including in town,” says Dr. Charles Lefevre, co-founder of the Oregon Truffle Festival and leading mycologist. “If you’re not hung up on species with commercial value, then you can actually find truffles nearly anywhere you find trees.” He emphasizes that most truffles are found on private land, so written permission from the land owner is a must.

There’s no way to spot a truffle from the surface, which is why I was trailing Gucci around the woods—her nose is sensitive enough to sniff them out. In parts of Europe, hogs are employed as they have an innate ability to detect truffles, though they can damage or eat them. Stopping a 300-pound creature determined to get at its snack takes some doing.

Dogs are easier to control, though they require training. They can be coached at home, but a professional will help iron out any bad habits.

“The goal when you’re training a truffle dog is to make hunting [truffles]the single best, most fun thing in the dog’s life,” says Dr. Lefevre.

He has a pair of Lagotto Romagnolo Italian truffle dogs, but more humble breeds can suffice. This year’s American Truffle Dog Competition, held in Eugene, was won by a Chihuahua named Gustave.

Some hunters dispense with dogs and use rakes—a tactic that is not considered cool in truffling circles.

“Rakes are indiscriminate,” says Dr. Lefevre, explaining that only ripe truffles are worth eating. “Since relatively few truffles are ripe at any given moment, raking produces mostly unripe truffles.” Dogs are trained to only sniff out mature truffles.

All this effort is so you can eat the things, but cooking with them isn’t entirely straightforward either, due to their potency.

“A lot of chefs think a heavy hand on truffle use makes the experience more luxurious,” says Abby McManigle, a chef at Brooks Wine who prepared a lunch at the festival. “I disagree. [Even] just shaving them on a dish can totally overpower [the flavor].”

At the lunch, she used truffles in all courses. The effect was subtle, often providing background notes rather than dominating the food. She likes to steep truffles in sauces or lay them under the skin of game birds or chicken. For the at-home cook, she recommends adding truffles to something simple like pasta, risotto, or roast chicken.

Truffles also need careful storage. They’re not like mushrooms, which can be left in a paper bag in the fridge. Instead they should be refrigerated in a sealed plastic container lined with a paper towel (in a single layer), which should then be opened once a day to let in air. Put fatty foods, such as eggs, cheese, and butter in the container to soak up excess aromas.

On a good day, Dr. Lefevre can harvest two pounds of truffles an hour. Despite my determined scrabbling around in the dirt, I didn’t find any. The elusiveness is part of the mystery, though. The excitement, after all, is in the hunt.