Spread a little pottery cup (capacity, 55ml) with a little oil, then put it into a bamboo steamer.
Add alkaline water to 100g of water and mix well. Mix rice flour, mung bean starch and tapioca starch, add water and mix until smooth. Put 270g water, brown sugar and Pandan leaves in a small pot, heat until it boils and until the brown sugar melts. Pour the hot syrup into the powder syrup and mix until combined. Filter it into a stainless steel pot.
Boil a 1/2 large pot of water, adjust to medium-low heat, soak the stainless steel pot in the hot water, cook the mixture for about 1 to 1 1/2 h minute, until it has a little consistency.
Pour the mixture into the measuring cup. The bamboo steamer with a small pottery cup is placed into the steamer, and the paste is poured into the cup until it is 85% full.
Steam on medium heat for 15 minutes, set it aside for 10 minutes to cool, soak the cup in cold water until it is completely cooled.
Add a little salt to the shredded coconut and mix well. Steam it on medium heat for 5 minutes, cover the steamed shredded coconut and set aside to cool.
Use a plastic knife to draw a circle along the edge of the cup and then take out the cake.
Enjoy your brown sugar kuih kosui with fresh coconut shreds!