SHANGHAI - In downtown Shanghai, Wei Xiang Zhai — a tiny, 37 sq m bistro with just 11 tables — is packed with customers every single day.

What draws crowds huddled shoulder to shoulder is a US$2 (S$2.56) bowl of noodles tossed in sesame paste.

The nearly century-old restaurant recently found itself in the global spotlight thanks to Tom Holland and Zendaya.

During their three-day trip to Shanghai in late July to promote their new movie Spider-Man: Brand New Day, the Hollywood couple visited the small restaurant twice for its signature sesame paste noodles and highly praised the dish in interviews. Dubbed “Spider-Man noodles”, the dish quickly went viral, and the waiting lines now feature a growing number of foreigners.

“We get about 50 to 60 orders from foreign visitors a day — well up from just a few years ago,” said Xue Mei, shift manager at Wei Xiang Zhai on Yandang Road in Huangpu district, who has watched the shop’s foreign clientele build steadily rather than explode overnight.

“An American food blogger with millions of followers came to film once, and after that we saw a surge in foreign tourists,” Xue said. “Then, when visa-free entry opened up for the Republic of Korea, visitors from there followed suit. It’s been a gradual climb.”

Asked about the secret behind the noodles’ enduring appeal, Xue credited the recipe, which has remained unchanged.

Beloved by locals and Hollywood royalty alike, the signature sesame paste is a finely balanced blend of peanut and sesame, leaving a delicate, sweet finish on the palate. The noodles themselves are made from a custom-milled, alkaline-rich flour, delivering a springy bite and a rich, wheaty aroma.

Another bestseller, the pork chop, features a signature soy sauce simmered according to a time-honored recipe, complemented by house-made chili oil.

Originally a cafe serving only coffee and cold beverages, the shop later pivoted to budget-friendly noodles and beef ...