Wash and soak the sago in water for 1 hour.
Drain the water and cook it in 3 cups of water for 5-7 minutes till the sago pearls becomes transparent.
When it is done drain the water and wash the sago again in cold water.
Peel the skin of mangoes and make them into slices.
Reserve one big slice for garnishing.
In a blender, blend the mango slices, evaporated milk, sugar, milk and mango juice (if adding) into a smooth paste.
Transfer the cooked sago to a big vessel.
when it is completely cooled add the mango milk mixture to this and mix well with a spoon.
Keep it in the refrigerator and serve chilled with finely chopped mangoes (which we reserved) on the top.