1.Add rice to a bowl and wash in several changes of water. Cover the rice with water and soak overnight.
2.Add water underneath a steamer pot and turn on burner until the water boils. Add cheesecloth to steamer insert then add the rice on top and cover. Steam for 10 minutes then turn the rice over and steam for 15 minutes.
3.While the rice is cooking, in a bowl, mix 1/2 cup coconut milk, 3 tablespoons sugar, and 1/4 teaspoon salt and microwave them for one minute. Leave it at room temperature and wait for the rice to be cooked. You need to do this before the sticky rice is cooked.
4.As soon as the sticky rice is cooked, put it all in the bowl with the coconut milk mixture. Stir until every grain of the sticky rice is coated with the coconut milk mixture, then cover and let the sticky rice grains absorb the coconut milk. Leave it for 20 minutes. Don’t worry if it looks soupy at first.
5.In a small pot mix 1/4 cup coconut milk, 1/4 teaspoon salt, and rice flour on low heat. Stir often so the rice flour will not get lumpy. Cook until it bubbles, then turn off the heat.
6.Add sticky rice to the plate with sliced mangos fanned around it. Pour the coconut sauce on top and serve immediately.