Rinse the sticky rice with tap water and use your hand to gently stir it. Drain the water to remove the excess starch. Repeat once, then add cold water to cover. Soak the sticky rice for a minimum of 1 hour, or up to overnight in the fridge. Once soaked, rinse again and drain the water.

Transfer the rice to a heatproof bowl, add about 2” of water to your steamer (not into the rice), place the heatproof rice bowl on the steaming rack in the steamer, and cover the steamer. Turn to medium-high heat to bring the water to a boil. When the steam starts to come out of the pot, turn to medium heat. Steam for 20 to 25 minutes, until the rice is cooked through, with no hard raw bits in the middle. Remove the pot from the stove. Let sit, covered, while you prepare the other ingredients.

Make the sauce when the rice is cooking. Combine the coconut milk, sugar, and salt in a saucepan. Cook over medium heat or medium-low heat until the mixture is hot and the sugar is melted. Do not bring the coconut sauce to a boil.

(Optional) If the coconut milk you’re using is thin: Combine the cornstarch and 4 tablespoons of water in a small bowl. Stir to completely dissolve the cornstarch. Add half of the slurry to the sauce. Stir immediately to thicken the sauce. You can adjust the thickness of the sauce by slowly adding a bit more water or cornstarch slurry, if needed. The sauce shouldn’t be too thick, but should coat the back of a spoon. (*Footnote 1)

Carefully remove the bowl of sticky rice from the steamer with your oven mitts on. Pour 1 cup of the sauce into the bowl. Stir to mix well until the sauce is fully absorbed.

The mango sticky rice is ready to serve when the rice mixture and the sauce cool to room temperature or lukewarm.

To serve, transfer 1/3 cup of the coconut rice to each of several small serving bowls or plates. Place the sliced mango on the side. Pour a few spoonfuls of the extra coconut sauce on top of the rice. Garnish with toasted sesame seeds, if using. (*Footnote 2)