For the Red Batter: In a medium bowl, combine the brown sugar and warm water. Stir until the sugar is completely dissolved. Let the mixture cool to room temperature. Once cool, add the tapioca starch and whisk vigorously until you have a completely smooth, lump-free liquid. Strain the batter through a fine-mesh sieve into a pouring jug or bowl to catch any undissolved bits. Set aside.

For the White Batter: In a separate medium bowl, combine the white sugar and milk. Stir until the sugar dissolves. Add the tapioca starch and whisk until completely smooth and lump-free. Strain this batter through a sieve into another pouring jug or bowl. Set aside.

Prepare your steamer by bringing plenty of water to a rolling boil. Lightly grease a heatproof dish or pan (like a 7-inch round or square pan) that fits inside your steamer.

Place the empty dish in the steamer to preheat for about 1 minute. This helps prevent sticking.

Start with the first layer: Give the red batter a good stir (tapioca settles quickly!). Pour a thin, even layer (about 2-3 tablespoons, or enough to just coat the bottom) into the preheated dish. Immediately cover the steamer and steam on high heat for 2-3 minutes, or until the layer is completely set and translucent.

Add the second layer: Carefully lift the lid. Quickly stir the white batter, then pour an even layer of the same thickness over the first set red layer. Cover and steam for another 2-3 minutes until set.

Repeat the process, always stirring the batter you're about to use, and alternating colors (red, white, red, white...). Continue steaming each layer for 2-3 minutes until set. Aim for a total of 11 layers (6 red, 5 white), finishing with a red layer. Steam this final layer for a full 3 minutes to ensure it's firm.

Turn off the heat and carefully remove the container. Allow the cake to cool completely at room temperature, about 10 minutes.

Once fully cooled, run a knife gently around the edges, invert the container, and unmold the cake. Cut into small pieces and serve.