1. Add 250 grams of sweet potato mash, 4 grams of yeast, 40 grams of white sugar, stir well, and pour 300 grams of flour.
2. Knead into a smooth dough (knead more than 100 times).
3. Cover the lid and ferment twice the size.
4. Knead the dough again, (if it is sticky, add a small amount of flour and knead it well) take half of the dough and roll it out into a rectangular shape.
5. Spread water on the dough.
6. Roll up.
7. Roll into long strips. Pull a pull.
8. Cut off the excess dough on both sides and knead it into a round shape.
9. Cut the remaining dough evenly.
10. Put it in a greased steamer.
11. Fermentation is twice the size.
12. Steam for 13 minutes on high heat and simmer for 5 minutes.
