Editor’s note: With the opening of the Expo Line’s extension to Santa Monica, locals have a new way to explore neighboring areas. The Daily Press will publish a weekly travelogue about what to eat, see and do near each of the stations along the Expo Line, continuing this week at the Expo/Crenshaw stop.

If I tell you that some of the best chocolate truffles in the region are being made in a nondescript building off an alley next to a gas station in South Los Angeles, will you believe me?

If so, you’re that much closer to, well, some of the best chocolate truffles in the region. If not, you’re just delaying the inevitable.

Maybe it’s an unlikely arrangement, a dessertery quietly doing business in a neighborhood that some Westside residents would scoff at even passing through. But there are sweet surprises to be found all over Southern California — as long as you’re willing to look for them.

A digital map of the area around the Expo Line’s Expo/Crenshaw station reveals the presence of a business near the corner of Crenshaw and Jefferson boulevards called Sweet Temptations, a name that could be affiliated with products or services other than truffles. The company’s associated website bears a different name, that of Yvan Valentin, and at this point curiosity wins out.

Valentin, I discover, is a French artisan chocolatier and pastry chef who traveled extensively before settling in Los Angeles in the mid-1980s to work at L’Orangerie. After eight years at the French restaurant he launched Sweet Temptations, his vehicle for distributing delectable treats to hotels, catering companies and specialty food stores. It’s largely a wholesale operation, but Valentin’s handmade truffles are available for purchase directly from his workshop at 3514 W. Jefferson Blvd.

Which is where the Expo/Crenshaw stop comes in.

Call ahead to confirm that the truffles, whose flavors include dark chocolate, praline, cappuccino and ivory cointreau, can be ordered for scheduled pickup. I opt for three half-pound boxes, which each cost $15 and come with 20 pieces.

Then come the directions: I’m told to bring cash and look for the “Grace Pastries” sign, which stands atop a building with a black gate that is tucked away from the adjacent alley. (Grace Pastries, in case you’re wondering, is long gone.)

Needless to say, this sounds like it’s going to be an adventure.

When I arrive at the Expo/Crenshaw station, which is a couple blocks south of the dessertery, I notice that the street divides transit stop in two. Eastbound trains stop just west of Crenshaw Boulevard; westbound passengers access the train east of the intersection. The area is primed to become a major transportation hub in the region once construction is done on the Crenshaw/LAX Line, which in 2019 will connect Expo Line passengers to Los Angeles International Airport.

I head north on Crenshaw, the massive West Angeles Cathedral standing as an omen of the religious experience that awaits me. After passing a strip mall and a cleaners, I cross the street towards a large parking structure and continue north to Jefferson Boulevard. Meandering onto the gas station property at the corner, I spot the aforementioned “Grace Pastries” sign hovering over a nearby alleyway.

The building’s shuttered storefront doesn’t offer much guidance, so I turn into the alley, passing a small homeless encampment. Sure enough, there’s an enclave tucked away from the alley where a worker pops out from behind a black gate. I follow him in.

Inside is an industrial bakery, a small table stacked with paperwork serving as its unofficial sales window, and I tell Valentin I’ve come to pick up three boxes of truffles. I hand an assistant $45 as Valentin retrieves a handle-less paper bag with my first name scrawled on the side in black marker.

The transaction is complete when, a few hours later, I open a box and bite into one of the divine truffles. The slightly firm outer layer gives way to ganache that is rich but smooth, dense but creamy, an extraordinary combination. “The result,” as an enclosed note reads, “is truly decadent.” And worthy of an adventure.

The Expo Line now has 19 stations covering 15.2 miles between Downtown Los Angeles and Santa Monica. A regular one-way fare is $1.75 and includes two hours of free transfers for riders using a TAP card. A daily pass good for unlimited rides on Metro is $7 and monthly passes are $100. Visit taptogo.net for more information.

Contact Jeff Goodman at 310-573-8351, jeff@www.smdp.com or on Twitter.