"Crispy rubies" in coconut milk (Thapthim krop)

1. Peel and grate the beetroot, blend with 100 ml water and strain – this is your natural red colouring.

2. Cut the water chestnuts into 7-8 mm dice and soak in the beetroot juice for 15 minutes until a lovely ruby red.

3. Drain and toss in the tapioca starch a little at a time so each cube gets a thin, even coat; shake off the excess in a sieve.

4. Drop into plenty of boiling water and cook for 2-3 minutes until the cubes float and the coating turns translucent; lift into iced water with a slotted spoon, then drain.

5. Warm the coconut milk with the sugar, salt and pandan leaves until the sugar dissolves, then cool and remove the pandan.

6. Put the rubies into glasses or bowls, pile crushed ice on top and pour over the cold coconut syrup.

Tip: "Thapthim krop" is the favourite cooling dessert of hot Thai afternoons: jelly-like outside, crunchy inside. Instead of beetroot you can colour it with a few drops of red food colouring; eat the rubies within 1-2 hours, as they harden after that.