For the pandan leaves, choose medium-aged, fresh, undamaged leaves for the best color without needing food coloring. Soak the fresh leaves in water to remove dirt, then wash thoroughly. Cut off the white base and yellow tips, then chop into short pieces. Blend 1.8 ounces (50 grams) of pandan leaves with 2/3 cup (150 ml) water, then strain to get 2/3 cup (150 ml) pandan juice. If you can't find fresh pandan leaves, you can use pandan paste—just add a little to 2/3 cup (150 ml) water until you get the desired green color and aroma.

Soak the mung beans in water for at least 3 hours until they expand, then steam or boil until cooked. 3.5 ounces (100 grams) of mung beans will yield about 5.3 ounces (150 grams) cooked if steamed, or about 6.3–7 ounces (180–200 grams) if boiled. If using whole mung beans with skins, adjust the weight after cooking as needed. (Note: The original mentions taro, but it's not included in the ingredient list, so skip this step.)

Green Layer – Mix all the green layer ingredients together until smooth. Strain through a sieve to remove any lumps. White Layer – Blend all the white layer ingredients in a blender until smooth.

Steaming the cake – Prepare a steamer with plenty of water and bring to a boil. Line the lid with a cloth or towel to prevent water from dripping onto the cake. If using a metal cake mold, lightly grease it with oil to prevent sticking. Step 1: Place the mold in the steamer. Step 2: Pour in a layer of green batter, cover, and steam on high heat. Step 3: When the green layer turns translucent (cooked), reduce the heat, pour in a layer of mung bean batter, and turn the heat back up to cook the next layer quickly. Step 4: When the mung bean layer turns translucent, pour another layer of green batter.

Continue alternating layers until you reach the desired number of layers. Note: Start and finish with a green layer. The mung bean (or taro) layers in between should be thicker than the green pandan layers. The steaming time for each layer depends on the size of your mold and the thickness of each layer. When a layer turns translucent, it's done. For example, if using a yogurt container as a mold and pouring each layer with a soup spoon, each layer takes about 5–7 minutes to steam.

Make sure each layer is fully cooked before adding the next to ensure even cooking. Prevent water from dripping onto the cake so the layers stick together well. Using a large mold gives a prettier cake but takes longer to steam, which can cause the green color to fade. Using a smaller mold keeps the color vibrant and makes a cake that's just the right size. Let the cake cool completely before removing it from the mold.