Place the rice in a sieve and rinse it several times with cold water until the water runs clear. Transfer the rice to a bowl and fill it with cold water. Cover it with a towel and allow the rice to soak overnight.

Drain the rice in a sieve then place the sieve atop a large pot of shallow, simmering water. (The sieve should not touch the water.) Place a towel over the sieve and then cover the pot with a lid and steam the rice for 60 to 70 minutes until it's cooked through. (Error on the side of overcooking the rice.) Add more water to the pot as needed.

While the rice is cooking, in a small saucepan set over medium heat combine 1 cup of coconut milk with 1/3 cup sugar and the salt. Bring the mixture to a boil, stirring until the sugar is dissolved. Remove the pan from the heat and cover it with foil to keep it warm.

Transfer the cooked rice to a large bowl and stir in the coconut milk mixture. Cover the bowl and let the rice stand for 30 minutes until it has absorbed all of the liquid. (The rice can be prepared up to this point 2 hours in advance and kept covered at room temperature.)

While the rice is standing, in a small saucepan combine the remaining 1/3 cup coconut milk with the remaining 3 tablespoons of sugar. Bring the mixture to a boil and cook it, stirring, for 1 minute. Transfer the mixture to a small bowl and refrigerate it until it thickens slightly.

When ready to serve, divide the rice among serving plates then drizzle it with the reserved coconut milk mixture. Sprinkle the rice with the sesame seeds and toasted coconut and serve the sliced mango alongside the rice. (Check out my video tutorial for the fastest way to cut a mango.)

Kelly's Notes:
To toast the coconut flakes, line a baking sheet with parchment paper and then sprinkle the coconut in an even layer. Bake the coconut for 7 to 10 minutes at 350ºF, stirring it halfway through, until golden brown.

If you've discovered you've undercooked the rice after adding the coconut milk mixture to it, don't panic! Transfer the rice back into the sieve and place the sieve atop the pot of boiling water. Cover it with a towel and a lid and re-steam it the same way you did the first time. Then remove it and stir in a second round of the coconut milk mixture and continue with the recipe as directed. The rice can absorb a significant amount of liquid, so don't hesitate stirring in a second round of the coconut milk mixture.