Steam the purple sweet potato with the skin on, let it cool, then mash it.
Add glutinous rice flour, salt, and sugar to the mashed purple sweet potato and mix well.
When the dough comes together, shape it into round balls.
Brush a little water on the surface of the dough and coat it with black sesame.
Heat a little oil in a pan and cook the bread on medium-low heat until golden brown on both sides.