1. Clean the sweet potatoes and steam them in the pot.
2. Pound into a delicate sweet potato puree.
3. Add 150 grams of low flour, 90 grams of butter, 2 grams of salt and 30 grams of sugar to the sweet potato puree and mix well.
4. Knead the dough, cover with plastic wrap and let rise for 15 minutes.
5. Roll out into thin slices.
6. Brush the surface with egg yolk liquid and sprinkle some black and white sesame seeds.
7. Cut into strips again.
8. Put it in the preheated oven and bake at 170 degrees for 10 minutes.
9. Remove and let cool before serving.