Exercise:
1. Boil the yeast with warm water and slowly pour it into 2.5 cups of flour. Knead by hand into smooth dough with moderate hardness.
2. Cover or cover with plastic wrap, put it in a warm place and ferment it for about 1 hour (shorter in summer) to twice its original size. The noodles made should be honeycomb-shaped.
3. Add baking powder and the remaining flour (a little) to the dough and continue to knead until the dough becomes hard. Not all the flour has been added. Cover with plastic wrap and wake for 10 minutes.
4. Divide the dough into six parts, roll each part into dough, then roll it into cakes, and leave it for another 5 minutes.
5. Just bake it in an oil-free pan over medium heat (the authentic one seems to be half cooked, and then bake it in an oven at 350C for 5- 10 minutes, which will be crispy outside and soft inside). As long as the heat is increased when it is almost ready, and the cake is slightly burnt, it will also have the effect of crispy outside and soft inside.