This January, Hung Lam launched a pop-up called Soup Junkie by making 70 bowls of noodle soup, selling them in an hour, and disappearing until he'd concocted another batch.
At his new FiDi takeout window, open on weekdays for coffee and lunch, Lam's Vietnamese soups appear with agreeable consistency, his pho ($9) deep and anise-sweet, the peach-colored bun rieu ($9) broth buoying soft tomatoes and clouds of a delicately scented crab omelet.
Each soup is a two-container affair, so that you can pour the broth into the bowl of noodles right as you're ready to eat. No mush.
Permanence has also allowed Lam to introduce solid food. His pulled-pork banh mi ($7) is nothing like Carolina 'cue; half-moons of cha lua (steamed pork) peek from a thatch of pickled carrots and daikon, as does slow-roasted pork with all the toasty meatiness of good carnitas.
And on Thursdays, you can pick up a container of some of the best banh cuon ($4) we've tasted in this country. The steamed rice crêpes, rolled around chopped pork and cloud ear fungus, drape from the chopsticks like washed satin. The instant your lips close around them, they melt into nothingness.
Once they disappear, though, you know where to find them again.
Soup Junkie, 388 Market St. (at Fremont St.); 415-291-0686 or soupjunkiesf.com