Blend together yogurt, condensed milk and mango pulp till well mixed in a blender.
Transfer into a bowl, add milk and mix well. Boil sufficient water in the lower deck of a steamer.
Pour the mango mixture into a silicon mould and place it on the upper deck of the steamer.
Put the lid on and steam for 15-20 minutes. Cool and chill in a refrigerator.
Decorate with mango slices and serve chilled.