Bring gula melaka, brown sugar, water and pandan leaves to a boil to dissolve the sugars. Strain the syrup.
Mix both types of flour and water in a mixing bowl. Stir the syrup into the flour mixture. Add alkaline water. Cook the mixture over a gentle low heat into a slightly thickened batter.
Spoon batter into greased small chinese teacups. Steam over rapid boiling water for about 15 minutes.
Mix grated white coconut with salt and steam for four to five minutes. Remove and spread on a big plate to cool.
Leave the steamed kuih kosui to cool completely before removing from the teacups. Toss kuih kosui in grated coconut and serve.