Add the sticky rice to a big bowl and water to cover 1” (2 cm) above the rice. Add the lye water and vegetable oil. Stir to mix well. The water will turn pale yellow due to the lye water. Cover the bowl and let soak in the fridge overnight, or for at least 8 hours.

In a large tray or bucket, add the dried bamboo leaves and water to cover. Weigh the leaves down with a big bowl filled with water or something heavy so all the leaves are submerged. If the tips of the leaves do not submerge, splash them with water and leave as-is.

Drain the water from the sticky rice. Rinse the rice a few times with running tap water. Use your hands to rub the rice a few times to remove any residual lye water. Drain again and set aside.

Drain the leaves and wipe each of them down on both sides with a paper towel.

Take one bamboo leaf, making sure it does not have any holes or tears. Use a pair of kitchen scissors to cut off 1” (2.5 cm) from the tough end (the base of the leaf). Face the smooth sides towards yourself. This is the side that will contain the filling. A third of the way along the leaf, wrap the tough end over the longer side and fold it into a cone shape, with the leaf sticking out from one end.

Hold the cone using one hand and begin to add the filling with your other hand. Add about 1 tablespoon of the sticky rice to the bottom and press it lightly with your finger. Add about 1 tablespoon of red bean paste. Keep adding the sticky rice while gently pressing and smoothing the rice, until it almost fills up to the low side of the bamboo leaf, leaving a 1/4” (1/2 cm) lip.

Take both of the short open sides of the zongzi between your thumb and index finger and fold the sides inwards, covering the rice. Fold the long leaves over the open area, tightening between your thumb and index finger to create a pointed triangular shape. Then flip the zongzi over and wrap the leaves around tightly to seal it. Tie the zongzi with a piece of twine, making sure it is cinching any area where the leaf might come loose, and tie it off in a way that will keep the leaves together, but not too tight that it squeezes the rice out (The rice will expand during cooking, and you want to leave space for it). For extra security, you can use another piece of twine to wrap the zongzi again, this time crosswise.

Cook on the stovetop: In a large pot, arrange the zongzi neatly to fill up the bottom of the pot with minimal gaps in between. Keep the zongzi as snug as possible so they do not move around a lot during cooking. Fill the pot with water, cover about 1” (2.5 cm) above the top of the zongzi. Add 1 teaspoon of lye water to the pot, stir to mix well. Bring the water to a boil, and then turn the heat to medium-low or low, and cover. Simmer the zongzi for 3 hours. Check the water levels periodically, replenishing the pot with boiling water when the waterline falls below the top of the zongzi.

Cook in an Instant Pot or pressure cooker: Arrange the zongzi in an Instant Pot or pressure cooker and water to cover. Keep all the zongzi in one layer with minimal gaps in between if possible. Close the lid and make sure the valve is sealed. For the Instant Pot, choose “Manual” at “High Pressure” and set a timer for 50 minutes. For a pressure cooker, heat over medium heat until pressure is added, then turn to low heat and cook for 50 minutes. Once done, let the Instant Pot release the pressure naturally

Drain the zongzi from the water. Serve hot, warm, or at room temperature with sugar, maple syrup, or any other type of sweetener/syrup you prefer.

Once the zongzi have completely cooled off, store them in sealed containers or ziplock bags. Store them in the refrigerator for up to a week, or in the freezer for 3 months. To reheat the refrigerated ones, you can microwave, steam, or boil them. To reheat the frozen ones, boiling or steaming works much better. For the refrigerated ones, steam or boil for 10 minutes. For the frozen ones, steam or boil for 25 minutes.