Make chewy sweet potato balls: Peel and cut the sweet potatoes into pieces, then steam until cooked. Mash the hot sweet potatoes quickly, then mix in the tapioca starch while the potatoes are still warm. If the mixture is too dry, add a little boiling water and knead until smooth and pliable. Divide into small pieces, roll into balls, and boil in hot water until they float. Transfer the cooked balls to an ice water bath to prevent sticking.

Mix the agar powder with 1/4 cup sugar (about 50 grams), then add about 3 1/3 cups fresh coconut water (about 800 ml). Use less water for a firmer jelly. Cook the mixture over the stove until boiling, then pour half into a mold for white jelly. For the remaining half, add a little butterfly pea flower coloring (optional) and pour into a round mold for a beautiful blue jelly.

Mix the grass jelly powder with 1/2 cup sugar (about 100 grams), then add 4 1/4 cups water (about 1 liter) and stir until dissolved. Cook over the stove until boiling, then pour into a mold and let it set.
- To make the coconut sauce: Combine coconut milk, unsweetened milk, 1/4 cup sugar (about 50 grams), and 2 teaspoons tapioca starch in a pot. Stir until smooth, then cook over the stove until boiling.
- Cut young coconut meat into thin strips and briefly blanch in boiling water.
- Cut the white agar jelly into thin strips.