On weekends, a banner unfurls from the awning at San Bruno's Pho de Nguyen and advertises Sitha Yim's "authentic Khmer food." In a time when pop-ups attract tens of thousands of social media followers and boxes of poppy seed bagels and black sesame egg tarts sell out months in advance, temporary restaurants seem trendy and glamorous, opportunities for chefs to cook with unrestrained creativity and without the headaches of managing payrolls and increasing rents.

But Yim, owner of Sitha's Khmerkitchen, is neither a pastry chef from an acclaimed restaurant taking a chance to craft her own menu nor a tech employee pursuing a passion while living off of a stable salary. Instead, she learned how to cook most of her Khmer (pronounced Kh'Mai) recipes from watching her mother and YouTube videos. Khmer cuisine refers specifically to the cuisine of the Khmer people in Cambodia.

A single mom who derives most of her income from the pop-up but also works three other jobs, Yim sources infant formula and diapers for Cambodian community members and carefully sculpts the brows of microblading clients in between dropping off orders of her twa ko, sausages stuffed with beef, rice and galangal (often described as a more citrusy relative to ginger).

Yim is part of a movement of entrepreneurs selling dishes that are hard to find locally and sourcing customers from immigrant communities on social media. With the lack of Cambodian restaurants on the Peninsula and just a handful of eateries in Oakland and San Jose, Sitha's Khmerkitchen, which pops up at Pho de Nguyen on weekends and also offers catering, is one of the few places to enjoy the cuisine's signature dishes in the Bay Area.

Inside Sitha's Khmerkitchen diners can find comfort in prahok ktiss, minced pork simmered in coconut milk with fermented fish. Served as a dip, it infuses the cabbage and eggplant with a forceful punch of umami and heat. Orders also pour in for the dancing shrimp salad containing seafood that is raw and translucent, barely visible underneath vibrant red chili flakes and bright green herbs.

However, just three years ago, Yim had never even prepared many of these dishes.

Arriving in San Francisco at age 7 after leaving Cambodia for "too cold" Chicago in 1984, Yim's childhood centered around Nagara Dhamma Temple, a Buddhist temple started by her parents. Prohibited from participating in extracurriculars, Yim washed dishes, cleaned and helped out seniors at the temple after school. Service to others, especially the elderly, became a paramount value in her life. "I help others before myself, and sometimes I shouldn't be doing that," she said.

In 2019, just before the pandemic, Yim moved back in with her mother under the fog-filled skies of San Francisco's Sunset District. Her younger brother had just died at the age of 33, and she had finalized her divorce after a six-year process and found herself as the sole caretaker for her two children. "I didn't know what to do," she said.

Yim, who had previously owned a doughnut shop and ran a Houston location of a Southeast Asian-Cajun seafood restaurant, took a suggestion from a friend and started selling sweet and spicy homemade Cambodian beef jerky through Facebook and Instagram.

"At first, I didn't know how to make (beef jerky). So I went to YouTube, and I'd be watching 10, 15, 20 (videos) all night," Yim said.

In the beginning, she made the jerky — traditionally served warm and crispy — at home, placing trays of beef strips in the living room, on the balcony and even on the stairs depending on where the sun was shining.

Eventually, Yim upgraded to a small dehydrator purchased on Amazon, but it couldn't keep up with mounting demand.

Thanks to social media groups populated by Cambodian Americans missing the taste of home, jerky orders ballooned from 10 to 400 pounds a week.

Selling primarily through Facebook and Instagram also meant that Yim's business was a two-way conversation, with customers reaching out whenever they craved chicken wings meticulously deboned and stuffed with spices and glass noodles or papaya salad prepared with the essential raw pickled crabs known as salted crab. Yim spent more time in the glow of cooking videos on her phone and continued seeking her mother's guidance, never wanting to turn down students craving their family's cooking or working professionals without the time to slowly simmer soups. "I just wanted to make every dish that they ordered ... all of a sudden, I had a full menu," Yim said.

Among Yim's social media customers was Phong Nguyen, the owner of Pho de Nguyen restaurant in San Bruno. The two of them started chatting about how business at the restaurant had slowed since the start of the pandemic. Nguyen and his fiance suggested that Yim host a three-day pop-up at the restaurant in December 2021. The event drew a crowd of customers seeking the opportunity to taste Yim's cooking in a restaurant setting. Nguyen then asked if Yim would be interested in taking over the space on weekends.

Yim knew that she could turn to her family for help.

"(My daughter) says she's seen how I've always struggled to survive, to have income, to put a roof over our head," Yim said about her daughter, Ping. She works as a server at the pop-up and buses tables in a similar fashion to how her mother once spent her evenings scrubbing floors at the family's temple. Yim's boyfriend and mother also help out in the kitchen.

Shortly after accepting Nguyen's offer to operate Sitha's Khmerkitchen on weekends, Yim started seeing her dining room crowded with customers, including Cambodian Americans traveling from across the United States. While the menu's pictures are slightly blurry and still bear the same bold white font as when Yim first shared them on Instagram Stories, her cooking now reflects hours of repetition and her obstinate dedication to Cambodian cuisine (while still conveying an understated, homemade presentation). The platter of raw vegetables that surrounds the prahok ktiss(spicy pork dip) is organized by color, with a row of verdant green bell peppers, lettuce and cabbage fading into translucent slices of white onion. She's figured out how to fit time into her schedule to pick up crawfish shipped to the airport from Louisiana, as her menu also includes an entire Cajun section that draws from her Houston days and includes gumbo, etouffee and po' boys.

Yim is eyeing a full restaurant as she continues to grow her customer base, but high food, rent and staffing costs still present substantial obstacles. In the meantime, Yim will continue her hectic weeks of home deliveries and shipping out sausages and jerky amid her many other jobs.

Regardless, she said she'll always prioritize her family, who are the motivation behind her restaurant. "I'm not just thinking about myself. I'm thinking about (my childrens') future, too. That's why when I work, I work. I don't complain, even though I'm tired: I still keep going," she said.

Sitha's Khmerkitchen is open on weekends inside Pho de Nguyen, 586-A San Mateo Ave., San Bruno; 415-798-4759, sithaskhmerkitchen.com. Instagram: @sithas_authentic_khmer_food.