Walking into Thim Hing Banh Mi (11107 Bellaire Boulevard at Boone), it's as if I've been transported to somewhere in Vietnam. The grayish-green linoleum has seen better days, the Formica- topped tables are chipped, the dark-brown diner chairs have that circa-1970s look, and if I worried about cleanliness, I would turn around and walk right out. The ladies behind the counter know me, but their dour expressions indicate no recognition. In fact, if friendliness were a requirement for patronage, Thim Hing would have no customers. The Thim Hing ladies never smile. It used to bother me, but these days, I think of them affectionately as the Banh Mi Nazis.

Smile or no, these women make a helluva xiu mai (meatball) banh mi and no matter how often or how many I eat, I don't get sick of them. I eat them for breakfast. I eat them for lunch. I eat them for a snack, and sometimes for dinner.

They don't toast the bread until you order, so the crust is always that perfect degree of crispness. Instead of the oblong bread roll so typical of Vietnamese sandwiches, they use a baguette, which is less doughy.

Before they fill it with meatballs, they add a house-made mayonnaise and douse the bread with the meatball broth, a slightly sweet tomato-based consomme. I think it's the meatball broth that gives this banh mi the addictive quality that keeps people coming back for more.

But truly, everything about the sandwich, from the perfectly toasted baguette to the pleasingly pickled carrots with just the right degree of sweet and sour, to the actual meatballs themselves, make this banh mi a knockout.

The only thing that mars the perfection of the sandwich is the fact that they are super-stingy with their meatballs. If you order the small $2.50 sandwich, you'll only get four quarter-size-diameter meatballs, barely enough to fill each bite. I tried ordering a $3.50 sandwich, but this added more bread, not more meatball.

I've discovered that the best thing to do is order the small $2.50 sandwich and request an additional dollar's worth of meatball. If you order it this way, you'll get a full meatball in each bite, and you'll definitely see why this is my favorite meatball banh mi in the city.