To prepare the sticky rice: Working in the sink, put the rice into a large bowl with plenty of water; stir well by hand. When the rice has settled to the bottom, pour off most of the cloudy water, refill and repeat until the water runs fairly clear. Soak the rice in plenty of water (so the water is approximately 2 to 3 inches above the rice) for 6 to 8 hours, preferably overnight (the grains will absorb water and grow in size). When ready to cook, drain rice well in a sieve.
Steaming the sticky rice: Set sieve over a large deep pot of simmering water (sieve should not touch water) and steam rice, covered with a kitchen towel and a lid, approximately 30 to 40 minutes, or until tender (check water level in pan occasionally, adding more hot water if necessary). When rice is translucent and somewhat tender, it is done.
Can also use a shallow heat-proof dish on the steamer rack. You can also purchase the special sticky rice steam baskets (steaming baskets and pots are available from Asian markets).
Preparing coconut-milk mixture: While rice is steaming, in a small saucepan bring coconut milk to a slow simmer, stirring constantly (hard boiled coconut milk will curdle). Add sugar and salt; stirring until sugar is dissolved; remove from heat. Keep mixture warm. Reserve approximately 1/3 to 1/2 cup coconut-milk sauce; refrigerate until cool and thicken slightly.
Transfer hot cooked rice to a bowl and stir in prepared coconut-milk mixture. Stir well with a spoon to make sure all the grains are well coated. Let rice stand, covered, approximately 20 to 30 minutes, or until coconut-milk mixture is absorbed (the rice should be a little mushy). Rice may be prepared up to this point 2 hours ahead and kept covered at room temperature.
Preparing Mangoes: Just before serving, peel mangoes and then thinly slice by cutting lengthwise through flesh to the stone; discard the stone. Peel the mangoes carefully so as not to bruise the fruit. Slice in half as close to the seed as possible, then slice each half into 1/2-inch (1-cm) slices.
Serve at room temperature. To serve, mold 1/4 cup servings of sticky rice in the center of individual dessert plates (an ice cream scoop works wonderfully). Drizzle reserved coconut-milk sauce over the rice mounds and sprinkle with sesame seeds. Arrange mango slices around the rice. Garnish with edible flowers or mint if desired.
NOTE: The finished dish can be kept, covered at room temperature for 6 to 8 hours. Do not refrigerate or the rice will harden!
Makes 4 to 6 servings.
* When sticky rice is cooked it turns from white to translucent, whereas long grain rice does the reverse.
** Try to get yellow-skinned "Manila" mangos, if you can, as the flavor is stronger and more acidic than the green and red-skinned South American varieties. Fresh ripe peaches may be substituted for the mangoes.
Mango With Sticky Rice Recipe: https://whatscookingamerica.net/fruit/mangostickyrice.htm