Rinse the glutinous rice under cold water until the water runs mostly clear. Cover with water and soak for at least 30 minutes (up to 4 hours for best texture). Drain well.

Place the soaked rice in a steamer lined with cheesecloth or parchment paper. Steam over simmering water for 20–25 minutes, until tender and translucent. The grains should be sticky but still distinct.

While the rice cooks, gently heat 1¼ cups coconut milk with ¼ cup sugar and ½ tsp salt over medium-low heat. Stir until the sugar dissolves completely. Do not let it boil. Remove from heat.

Transfer the hot steamed rice to a bowl. Pour about 1 cup of the warm coconut mixture over the rice and gently fold to combine. Cover and let sit for 15–20 minutes so the rice absorbs the coconut mixture.

To make the coconut drizzle, combine ½ cup coconut milk, 1 tbsp sugar, and a pinch of salt in a small saucepan over low heat. Stir the cornstarch with water, add to the pan, and cook gently for 1–2 minutes until slightly thickened. The sauce should be silky and pourable.

To serve, spoon the sticky rice onto plates. Arrange sliced Ataulfo mango alongside or fan it over the rice. Drizzle with the thickened coconut sauce and garnish with toasted sesame seeds or coconut flakes if desired.

 Serve slightly warm or at room temperature. Enjoy!