Banh Tet and banh chung (the square cake version) are available year long and for the Lunar New Year in Vietnam. It's a sticky rice cake with various fillings, some are sweet and some are savory. Mung beans, pork, and sticky rice are the core ingredients. Raffia string is usually used to tie the cakes but I've used kitchen twine. Also, traditionally these are more elaborately trussed than tied, like I did here to simplify. I wrapped the cakes in foil, that's Andrea Nguyen's move. Once the cakes are cooked you can wrap them in gold or red plastic ribbon for luck in the new year.
Use long-grain glutinous rice, and split yellow mung beans.
You really need a full day to prepare these. Or, save time with these make aheads: Make mung bean puree up to 3 days in advance. Cbanana leaves 1 day ahead of time and sandwich between layers of damp paper towel; chill in zip-top bags. Marinate pork for at least 2 hours, so you can prepare your pork rolls the night before assembling.