Mix all the dough ingredients well in a large bowl. Cover with plastic wrap.
Place the large bowl in a steamer (or in a large covered pot). Bring the water to a boil and continue steaming for 20 minutes. Stir once during the process to ensure even cooking.
Remove from the pot and stir with chopsticks to help it cool. Transfer it to a greased plate or salad bowl. Then knead for 3-4 minutes with greased hands. Be careful, it will be hot, so if you have gloves, it's better. Wrap the dough well with plastic wrap and refrigerate until cool.
When the dough is well cooled, use your thumb and index finger to form a circle around the dough and press a ball. Flatten and wrap your filling with it.
Roll the ball in the bowl with shredded coconut, place in a cupcake mold. Repeat the process to make all the coconut balls. Put everything in the fridge for 2 hours.
Notes
For the red bean paste, it's better if it's very thick rather than liquid