Begin by preparing the mung bean layer. Steam the soaked mung beans for 20 minutes until they’re soft. Transfer to a blender or food processor and blend with the coconut milk until smooth. Set aside to cool slightly.

In a large mixing bowl, combine the tapioca starch, rice flour, and sugar for the mung bean layer. Gradually add the blended mung bean mixture, stirring until a smooth, lump free batter forms. Adjust sweetness if needed. Set aside.

In a separate bowl, prepare the green pandan layer by mixing the tapioca starch, rice flour, and sugar. Stir in the coconut milk and pandan juice gradually, mixing until smooth and evenly green. Make sure no lumps remain in the batter for a glossy finish.

Prepare a steamer by filling it with water and bringing it to a gentle boil. Grease an 8 inch round pan with a light layer of oil to prevent sticking. Place the pan in the steamer to heat slightly before adding the first layer.

Pour a thin layer (about 1/4 inch) of the green pandan batter into the heated pan. Cover and steam for 5-7 minutes, or until the layer is set. The layer is ready when it’s firm to the touch but still slightly translucent.

Once the first layer is set, pour an equal layer of the mung bean batter on top, covering the previous layer entirely. Steam this layer for another 5-7 minutes until set. Continue alternating layers of green and yellow, steaming each one until firm before adding the next.

After the final layer is added and steamed, cover and steam the whole cake for an additional 15 minutes to ensure all layers are fully cooked through. This steaming ensures the cake has a cohesive, jelly like texture.

Remove the cake from the steamer and allow it to cool completely in the pan. Once cooled, run a knife around the edge, then slice into diamond or square pieces. Serve at room temperature with a light sprinkle of shredded coconut if desired. This cake is best enjoyed fresh, showcasing the pandan's aromatic flavour and the soft, chewy texture of each layer.