@ipsedixit @Chowseeker1999 Thank you for this! I have since visited (and really enjoyed!) Best Noodle House, and I did find the Youpo noodles pretty similar to (and just as delicious as) the biang biang noodles I’ve had around, despite the different names.
And it may not be worth anything significant, but on the wikipedia page for biangbiang noodles (which surprisingly is a real thing that exists), it lists 油潑扯麵 (yóupō chěmiàn) as an alternative Chinese name of the dish. I know absolutely nothing of the language, but thought that was interesting. From an abbreviated google search, it does seem like Youpo noodles are also a Shaanxi specialty. Regardless, great restaurant, great dish.