I had a few banh gio when I was in Saigon at the store nearby my studio. I think that dish is from the Northern region of Vietnam. I liked it for my breakfasts or light dinners. I did not have a chance to try to make some by myself until I relocated to Austin. It is easy to search recipes of banh gio on-line. I found one which did not require me to use banana leaves to wrap. It is covered in banana leave in a pyramid shape supposedly.
My 1st attempt of making banh gio was not that good because I did not cook that corn starch mixture long enough. I tried to fix it by increase a bit microwave cooking time. It tasted good anyway.
Here is the banh gio recipe by Cathy Chaplin. It is totally replaced with vegetarian filling.