Thai
Rinse the rice until the water runs almost clear, then cover with fresh water and soak for at least 4 hours or overnight.
Drain the rice, spread it in a steamer lined with cheesecloth, lay the pandan leaves on top and steam over boiling water for 25-30 minutes, until the grains are translucent and tender.
While the rice steams, heat 250 ml of the coconut milk with 80 g of sugar and 1/2 tsp of salt, stirring until the sugar dissolves; do not let it boil.
Transfer the hot rice to a bowl, pour the sweet coconut milk over it, stir gently, cover and leave for 20 minutes to absorb.
For the topping, whisk the rice flour into the remaining 150 ml of coconut milk with 10 g of sugar and 1/4 tsp of salt, and simmer for 2-3 minutes until slightly thickened.
Peel the mangoes, cut the cheeks off the pits and slice them crosswise.
Serve a mound of rice with sliced mango, spoon the topping over the rice and sprinkle with the mung beans.