Indonesian Putu Bambu (Steamed Rice Cake in Bamboo)

• Prepare the topping by mixing the grated coconut and salt and steam for 10 minutes over medium heat

Steam the rice flour:

• Put the rice flour on a steaming plate or you can line your steamer with banana leaves and put the flour on top. Cut pandan leaves into smaller pieces and tuck them inside the flour to impart some flavor. Wrap the lid of your steamer with a cloth so no water will drop on the flour. If you have a bamboo steamer, you don't have to worry about water condensation. Steam over medium heat for 25 minutes
• Remove from the steamer and let it cool down completely. The steaming process adds some hydration to the flour and also to get rid of the "raw" taste of the rice flour

Prepare the putu mixture:

• Get the steamer ready with some water on high heat. Place the cooled-down steamed rice flour and salt in a large mixing bowl. Adding the water a little bit at a time. I can't stress enough the importance of not dumping the water all at once. Continue until you use up most of the water (or all). The flour should feel "damp" and you will see some large and small lumps. That's normal
• Use a strainer to strain the mixture and you will get fine granules. They should feel airy and powdery. DO NOT press on this mixture

Make your own mold:

• Cut some banana leaves or use aluminum foil. Cut into 3 inches wide, about 4 inches long. Use something round, about 1 to 1 1/2 inches in diameter to roll into tubes and secure with a stapler. Make about 15-16 of them. Cut out about 2 x 2 inches square of parchment paper or banana leaves as a base
• Put the tube on top of the base. Fill the tube with rice flour mixture (about 1/2 of the height of the tube. DO NOT PACK/PRESS the flour. It is supposed to be loose, then spoon some coconut sugar and then top with more flour mixture and use your finger to gently scrape off to level the top
• Place the tube in the steamer and steam over medium heat for 15-20 minutes. When they are done, remove from the steamer and gently remove the banana leaves or foil and put the kue putu on a plate and proceed to serving step

If you use idly maker (I haven't tried this myself):

• The process is very similar to using kueh tutu mold. Layer with flour mixture, then the gula jawa and then cover with more flour. The only difference is you don't need to remove any mold or flip over anything. It's probably much easier. Steam for about 10-15 minutes. When they are done, proceed to serving step

If you have bamboo tubes:

• Put some of the flour mixture inside the tube (with the coin already inserted inside the pipe), about 1/2 of the height of the tube. DO NOT PACK/PRESS the flour. It is supposed to be loose, then spoon some coconut sugar and then top with more flour mixture and use your finger to gently scrape off to level the top
• Place the tube in the steamer and steam over medium heat for 15-20 minutes 
• When ready, push the Putu Bambu out. You can use a chopstick and slowly push the coin out and the Putu Bambu will slide out. Don't panic if it doesn't really hold its shape. Line your serving dish with banana leaves if you want. That's how it was served in Indonesia

Serving:

• Sprinkle with the grated coconut and salt mixture along with a generous amount of sugar on top of it