In a small pot, add light coconut milk and rock sugar. Bring to a boil on medium-high heat and then reduce to low heat and simmer for 5 minutes until sugar has completely dissolved, stirring occasionally. Do not cover. Transfer this to the freezer to cool down completely.

In a medium size pot of water (about 5 cups of water), bring to a boil on high heat. Once the hot water reaches boiling point, add tapioca pearls. Reduce to medium heat or to a rolling boil, boil for 10 minutes uncovered. Stir occasionally. Then turn off the heat, cover and let it sit for another 10 minutes until the pearls have softened and are completely translucent. If you see a small white dot in the center of the pearls, let them sit in the hot water covered for another 2-3 minutes to become fully translucent.

Strain cooked tapioca in a fine mesh strainer and rinse off with cold running water. Leave it submerged in the cold water until assembly, but make sure to strain out as much excess water as possible.

Peel and dice mangoes into small bite-sized cubes.

Once the coconut milk mixture has cooled, add in cooked sago and diced mango and mix well. Garnish with mint and serve chilled!