Peel the sweet potatoes, boil them, and mash them.
Add black sesame seeds, glutinous rice flour, salt, and sugar to the mashed sweet potatoes and mix well.
Divide the dough into 8 equal parts and shape them into balls.
Roll the dough balls in sesame seeds to coat the surface.
Heat a pan with a little cooking oil and cook the buns on low heat, flipping occasionally.
When they are golden brown, they are done.