Children across the island learn early to identify the passing street food vendors from the sounds they make. A tinkling sound produced by an aluminum spoon knocking against a porcelain bowl means that the bakso (meatball) vendor is around the corner. A clapping sound created by a bamboo stick hitting a wooden block means that the mie ayam (chicken noodle) seller is nearby. While a repeated high-pitched whistle means that kue putu seller is around.
The cake is made of rice flour, pandanus leaves and palm sugar. The pandanus leaves are boiled and the water is used to give the flour its green color and aroma.
In the past, the mixture of flour and palm sugar was placed inside short bamboo tubes before being steamed. Nowadays, kue putu sellers use the more practical, longer lasting, but less aesthetic and probably more dangerous, plastic pipe.
The pipes are placed over tiny holes drilled into the top of rectangular tin can. Inside the tin can is a burning stove and a pan filled with boiling water. The steam released through the tiny holes cooks the cake in no time at all. Kue putu is served warm with freshly grated coconut and are really delicious.
