Dice the water chestnuts into chunks and toss with the red food coloring until evenly coated. Throw the colored water chestnuts into a bowl. Sprinkle with the tapioca flour and mix well to coat.
Pour out the contents into a colander and shake off the excess flour (make sure there's not too much flour or the texture will be too gummy and you will lose the water chestnut flavor).
Put the floured chestnuts into a pot of boiling water. Boil until the flour turns translucent and the red of the water chestnuts is all that's left, about 2 minutes. Remove and drain the water chestnuts. Toss into a bowl of ice cubes and water.
To serve, scoop the Red Rubies into small glasses. Drizzle Jasmine Simple Syrup and coconut milk or cream on top. Serve immediately.
Jasmine Simple Syrup:
Boil the sugar and water with the jasmine essence to flavor your syrup. Pour into squeeze bottles. Refrigerate.
If you can't find jasmine essence, soak fresh jasmine in water overnight or use rose essence or extract.