Make a pandan-infused coconut mixture by warming together the Coconut milk and Water in a saucepan with the tied Pandan leaves, Granulated sugar and a pinch of Fine salt; heat gently just until the sugar dissolves and the mixture is fragrant, then let it cool and remove the leaves.
In a mixing bowl, whisk the Tapioca flour and Rice flour together until evenly combined and free of lumps.
Slowly pour the cooled coconut-pandan liquid into the flour mixture while whisking to form a smooth, pourable batter — adjust with a little extra water if it seems too thick, or a touch more flour if too thin.
Divide the batter into two bowls; leave one pale and tint the other with a few drops of Red food coloring until you reach the desired shade.
Prepare a steamer and bring the water to a steady simmer. Lightly grease a shallow square or rectangular cake tin with Neutral oil so the layers release easily.
Pour a thin, even layer of one batter into the prepared tin (just enough to cover the base), steam until the surface is set and no longer wobbly, then very lightly brush or spray the surface with a little oil to help the next layer adhere.
Repeat with alternating colors, pouring each thin layer and steaming until set before adding the next, until all the batter is used and you have many even layers.
After the final layer is added, steam the whole cake for a little longer so the center sets through, then remove from the steamer and allow the kuih to cool completely in the tin.
When cool, invert the cake, slice into diamonds or squares, and serve. Store covered at room temperature for a day or refrigerated for longer keeping.
