Drizzle 50 ml boiling water on tapioca flour. Knead to form an elastic dough, dusting with tapioca flour if too sticky. If too dry, wet hands before kneading. Divide dough into 2 equal size pieces. Add red colouring (or palm sugar) to one piece. Knead till colour is even. Roll into a rope 1½ cm thick. Cut crosswise 1½ cm wide. Dust thoroughly with tapioca flour to prevent sticking, and set aside. Add green food colouring (or pandan juice) to remaining dough. Proceed as for red dough to make jelly beads.
50 ml boiling water, 60 g tapioca flour
Divide tapioca dough into 2 equal size pieces. Add red colouring to one piece. Knead till colour is even. Roll rod-shaped 1½ cm thick. Cut crosswise 1½ cm long. Dust thoroughly with tapioca flour to prevent sticking, and set aside.
2 drops red food colouring
Add green food colouring to remaining piece of dough. Proceed as for red dough to make green jelly beads.
3 drops green food colouring
Cook tapioca jelly in boiling water till floating, stirring to prevent sticking. Remove with slotted spoon to a bowl. Sprinkle with sugar (to prevent sticking). Mix thoroughly. Set aside. Discard water.
boiling water, 1 tsp sugar
Place rock sugar, boiling water and pandan leaves in a small pot.
75 g rock sugar, 1 cup boiling water, 6 young pandan leaves washed and knotted together
Add yams and bring to a boil. Cover and simmer gently over low heat till just soft, about 7 minutes. Don't use high heat or yams will disintegrate. Discard pandan leaves. Remove yams with slotted spoon to a bowl.
1 cup yam diced 1½ cm
Place sweet potatoes in the pot. Bring to a boil, cover and simmer gently till just soft, about 5 minutes.
½ cup orange sweet potatoes diced 1½ cm, ½ cup purple sweet potatoes diced 1½ cm
Add salt, coconut milk, and boiling water. Stir to mix thoroughly. Taste and adjust sweetness if necessary. Add a little water if liquid is too rich.
1 pinch salt, 200 g undiluted fresh coconut milk, ¾ cup boiling water
Turn off heat as mixture comes to a gentle simmer. Add tapioca jelly and yam. Stir through.
Serve bubur cha cha hot or chilled.