Combine coconut milk, water, salt and sugar in a mixing bowl. Combine the flours and sift into the bowl. Mix everything gradually together until the sugar dissolves. Strain the mixture to remove any lumps and leave aside to rest for 10-15 minutes.
Heat oil in a small saucepan and place the kuih ros mould in the hot oil. Remove and dip three-quarters of the mould into the batter. Take it out and put the batter-coated mould into the hot oil, reducing the heat to low. Once the batter is semi-set, slowly release the kuih ros from the mould with a pair of chopsticks.
Allow the kuih ros to fry in the oil until golden brown. Dish out and drain on several layers of paper towels. Leave them to cool then store in an airtight container.