Rinse all ingredients with a little salt, then drain. Cut pandan leaves into 2-inch pieces. Split or crush sugarcane before cooking.

Place a few slices of sugarcane at the bottom of a pot. Add ingredients like corn silk, plantain leaves, dried winter melon, pandan leaves, and any other cooling herbs. Top with the remaining sugarcane. Pour in 17 cups filtered water (4 liters) and bring to a boil.

Once boiling, skim off any foam, then reduce to a simmer and cook for 15–20 minutes. Remove all solids, add rock sugar to taste, and continue cooking until the sugar dissolves. Stir well, then turn off the heat and let cool.

To make the grass jelly:
- Mix the grass jelly powder and sugar in a bowl, then add to a pot with 3 1/2 cups filtered water (800 grams). Stir until dissolved and let the mixture rest for 30 minutes.
- Place the pot on the stove over medium heat, stirring constantly until the mixture boils and thickens. Lower the heat and cook for another 3–5 minutes, then pour into a mold.

Once the grass jelly has cooled, refrigerate until set, then cut into bite-sized pieces. Soak chia seeds in water until they expand.

To assemble:
Spoon grass jelly into a glass, pour in the winter melon herbal drink and add chia seeds. Top with ice cubes for a cool, delicious drink perfect for hot days.