Cut each water chestnut into four pieces for large, satisfying bites.

Divide the water chestnuts into portions and toss each portion with your preferred food coloring.

Coat the colored water chestnuts evenly with tapioca starch, one color at a time. Toss them back and forth to ensure the starch sticks well and forms a good coating. This helps the coating stay on during boiling. Sift the coated pieces through a strainer to remove excess starch, then set aside.

Bring water to a boil in a pot. Once boiling, add the coated water chestnuts, cooking one color at a time so the colors stay vibrant. When you first add them, do not stir, or the starch may come off.

When the red rubies float to the surface and the coating looks translucent, they are done. Use a slotted spoon to transfer them immediately into a bowl of ice water or water with ice. This helps the coating become chewy and prevents it from getting mushy. Once cooled, drain and place in a serving bowl.

Mix granulated sugar and water in a 1:1 ratio (for example, 1 cup sugar to 1 cup water). If you have pandan leaves, tie a few together and add them for extra fragrance. Heat until the sugar dissolves, then bring to a boil. Remove from heat and let cool to make a syrup for serving. To serve, spoon the red rubies into bowls, pour over coconut milk, add syrup to taste, and top with a little crushed ice for a refreshing finish.