Soak the sticky rice in water for at least 8 hours or overnight.
Drain and wash the rice with a new batch of water. Repeat the process until the water is clear. Drain the rice one last time using a flat winnowing basket.
Soak the green beans for at least 4 hours before boiling them. Make sure to season the beans with sugar and salt while boiling them.
Combine crushed pepper, sugar, salt, and minced shallots to marinade the pork belly for roughly half an hour.
Stir-fry the sticky rice in a skillet with extracted pandan leaf juice, coconut milk, sugar, and salt. Keep stirring the mixture until the liquid is fully evaporated. Remove from heat and let the rice cool.
Pound the green beans into a paste-like mixture and spread it over a flat surface. Place a long piece of pork belly over the spread bean and seal the meat with another layer of green bean paste.
Roll the green bean and pork filling into a cylindrical shape, making sure the bean covers the pork belly completely.
Layer a flat surface with two large banana leaves (around 15.7x19.7in) with smooth, shiny surfaces facing outward.
Place another two smaller leaves (11.8x15.7in) in the same direction as the larger ones.
Continue to put another larger leaf in the middle of all the assembled leaves.
Place a bamboo string under the first leaf layer.
Put a decent amount of sticky rice over the leaf surface.
Transfer the cylindrical filling over the sticky rice bed and place it in the center.
Pour more sticky rice over the filling to cover it.
Hold the two horizontal ends of the banana leaves and fold them in half. Then roll the cake tightly and secure the shape using the bamboo string placed in the middle of the Banh Tet.
Fold one end to flip the cake vertically on that same folded side. Pour more sticky rice into the remaining open end of the bánh tét to evenly distribute the sticky rice.
Fold the last open end of the cake and seal both rectangularly cut banana leaves placed on each side.
Take another 4 rectangular banana leaves to secure both ends of the bánh tét. Place the leaves in a crisscross pattern over each side of the cake to prevent water from seeping in while boiling.
Take two bamboo strings and tie them in the vertical direction of the bánh tét to tightly secure both ends of the cake.
Then, wrap the bamboo trips horizontally around the cake. Start from the top and work your way down to the bottom of the bánh tét. Later on, remove the rubber bands and the vertical bamboo strings leaving the horizontal strings only.
Layer the bottom of the pot with any remaining banana leaves to prevent burning and start placing in the cake. Submerge the cake fully in water and let the fire simmer for 8 hours. Keep the water boiling lightly and not vigorously.
Make sure to refill the water so the bánh tét is always submerged and cooked evenly. Remove the cake and give them a cold water bath to cool off and clean the cake exterior.
For cutting the cake, remove the outer banana layer and place a bamboo string under the cake. Pull both ends of the string in opposite directions to cut the cake into a wheel shape. You can also use a knife for cutting.