-
1
Peel the water chestnuts and dice into 1 cm cubes, then transfer to a bowl and add a few drops of red food colouring. Toss until the cubes are evenly coloured, turning them repeatedly so the dye reaches the cut surfaces rather than sitting only where it first lands. The colouring should be uniform — no white patches remaining on the cut surfaces.
-
2
Add the tapioca flour to the bowl, 2–3 tablespoons at a time, and toss to coat each cube thoroughly, working in stages so the flour is absorbed gradually and does not clump into damp pockets. Shake the cubes in a sieve or colander to shed all excess flour, since loose flour in the water will cloud the boiling pot and thin the coating. Every cube should carry a thin, even, dry film — no clumping, no bare patches.
-
3
Bring a generous volume of water to a vigorous boil, then drop the floured cubes in and stir once to separate them, so they cook freely rather than fusing together. Watch closely: within 1–2 minutes the coating changes from opaque white to translucent — this is where the dish lives or dies, because white means the coating will taste raw and floury at the table, while any further cooking beyond that translucent moment causes it to dissolve into a gluey, indistinct film rather than the desired elastic, clearly defined shell.
-
4
Lift the cooked pieces immediately with a slotted spoon and transfer to a bowl of cold water, so the coating sets firm and cooking stops before the shell has any chance to soften further. Turn them gently to rinse away surface starch, which would otherwise make the pieces stick together in the bowl. Each cube should feel firm to the touch — the interior water chestnut resisting pressure, the coating supple and slightly tacky but intact.
-
5
Combine the thin coconut milk, dissolved palm sugar, and a pinch of salt, stirring well so the sugar is fully absorbed and does not settle. Taste the liquid — it should be gently sweet, faintly saline, with no raw sugar edge — then chill until cold, because warm coconut milk would melt the ice immediately and blur all the textures the dish depends on.
-
6
Place a portion of coated water chestnuts in a bowl over a mound of crushed ice, then ladle the cold sweetened coconut milk over and around. Add a few drops of jasmine water and serve at once — the ice must still be present at the table, maintaining the cold against which the snap of the water chestnut and the give of the tapioca shell are properly felt.