Soak the glutinous rice in 4 cups of water for 8 hours or up to overnight. Drain.
Line a bamboo steamer with a clean tea towel or steaming cloth, then fill it with the drained sticky rice. Bring the edges of the towel over the top and cover with the bamboo lid.
Place the steamer in a wok or pan with just enough simmering water to come no higher than the bottom of the steamer and cook over high heat until fully cooked through, 20 to 30 minutes.
Meanwhile, combine the coconut milk, sugar and salt in a saucepan and bring to a simmer, stirring until the salt and sugar are dissolved. Turn off the heat.
Transfer the sticky rice to a mixing bowl. Pour in three-quarters of the coconut milk mixture, stirring to combine evenly. Let the rice sit, 20 to 30 minutes.
Meanwhile, dissolve the cornstarch in 1 tablespoon water, then stir it into the remaining coconut milk. Bring to a boil to thicken, then turn off the heat and set aside. Serve the rice with the mango and additional sauce on the side.
Copyright 2017 Asian Food Channel. All rights reserved.