Toast the coconut: Add the dried shredded coconut in a dry pan and cook on medium heat (while stirring continuously) until lightly toasted. Set aside on a large plate. This happens very fast so never leave it.
Fill a large pot a little over halfway with water and place on the stove using medium heat. Combine sugar and sesame seeds in a small bowl. Set aside.
Add the glutinous rice flour, mashed sweet potato, food coloring and water in a large bowl. Mix and knead with your hands until a soft dough is formed. It will be cohesive (like a soft play dough) but not dry or sticky. Add a teaspoon more water if it’s too dry or a bit more flour if too sticky. Divide the dough into 12 balls.
Once the water starts to simmer, shape each dough ball into a flat oval-ish shape. Place a ball between the palm of your hands and gently squeeze to flatten. Turn it over and do the same thing on the other side. Gently drop into the simmering water and cook until it floats to the top (about 2 minutes).
Place the cooked ones on the paper towel-lined plate to drain for a few seconds before transferring to the toasted coconut. Dip each side to cover then sprinkle with the sesame-sugar mix before serving.
*The coloring/flavoring is optional. Use a purple or orange-colored sweet potato instead.