"Bahn mi thit nuong at a pavement stall in front of 37 Nguyen Trai in
District 1 (about a block past an intersection of at least 3 or 4
streets that appears as a circle on my map). The sandwich lady sets up
around 5:30 p.m., and sells some of the most delicious sandwiches I’ve
ever had. They consist of grilled pork meatballs on a French roll with
barbeque sauce, cilantro, and some other veggies. At 5,000 VD (roughly
33 US cents) each, you can’t go wrong."
There’s more on eGullet.