There are many different types of leaf cake (banh la) which are eaten in Vietnam. The Vietnamese leaf cake is similar to the Thai dish Khao Tom Mud and is made with sticky rice and other ingredients seemed inside a leaf. The shape of the leaf cake, the leaf which is used and the ingredients which are cooked with the rice, however, vary depending upon the occasion when the dish is eaten and what part of Vietnam it is cooked in.
In the north of Vietnam the popular version version on the leaf cake is the square banh chung leaf cake, Banh chung tends to be a savoury cake with sticky rice, pork, mung bean and seasoning wrapped in the leaves of the la dong plant. By way of contrast in the south of Vietnam the version of the leaf cake (bahn tet) which is more commonly eaten is cylindrical and wrapped in banana leaf, although the ingredients in bahn tet also tend to be pork and mung bean paste. If you prefer a sweet leaf cake to savoury one then try banh la dua which is sticky rice, peanut, banana and coconut cooked in a cocount leaf. Banh la dua is popular in the Mekong delta and you are likely to find being sold in the floating markets of Can Tho.