Most of the fancier places won't have banh mi's. That is considered street food.
Look to see if this place has banh kot. It's SO good. It's a coconut milk mini pancake (like golf ball sized) with a shrimp inside, and you top with basil, mints and nuoc mom (fish-sauce sauce). The best I had was in San Jose, and I am making brezofleur go try them.
Banh Khot #5 | Yelp
And close up:
Banh Khot #5 | Yelp
Also try bo luc lac (shaken beef). It's pieces of filet mignon in butter and garlic. It's usually about $10-15, but it's so good.