Soak the rice in 1 cup water for 20-30 minutes, OR up to 4 hours.
Do not drain the rice. Simply add 3/4 cup (more) water, plus 1/4 can coconut milk, 1/4 tsp. salt, and 1 Tbsp. brown sugar. Stir this into the rice.
Bring to a gentle boil, then partially cover with a lid (leaving some room for steam to escape). Reduce heat to medium-low (#2.5 on the dial).
Simmer in this way for 20 minutes, or until the coconut-water has been absorbed by the rice. Turn off the heat, but leave the pot on the burner with the lid on tight. Allow to sit for 5-10 minutes.
To make the sauce, warm (do not boil) the rest of the can of coconut milk over medium-low heat (5 minutes). Add 3 Tbsp. sugar, stirring to dissolve.
Taste-test the sauce for sweetness, adding more sugar if desired. (note that it will taste less sweet when added to the rice).
Add scoops of rice (portion out 1 scoop per person) directly to the sauce pot and stir over low heat, gently breaking apart large lumps, but leaving smaller lumps/chunks). Now add the mango pieces and gently stir until everything is warmed through. Portion
out into serving bowls, making sure everyone has equal amounts of rice, mango, and plenty of sauce. Enjoy!