1. Steam the sweet potatoes, let them cool, and press them into puree with a spoon.
2. Except the butter, pour all the ingredients into the bread machine and knead it into a smooth dough. Then add butter and knead until the dough can be stretched into a film.
3. Cover with plastic wrap and ferment in a warm place to double its size.
4. Press and exhaust the dough, divide it into 8 equal parts, cover with plastic wrap and wake up for 15 minutes.
5. Smooth the dough down and roll it into an oval shape with a rolling pin.
6. Spread pork floss in the middle.
7. Then roll up from the short side and pinch tightly at the closing and both ends.
8. Put it in the oven and ferment to double the size. Use a sharp knife to cut a deep mark in the middle of the dough and brush the edge of the knife with egg wash. Preheat the oven to 175 degrees, and bake the middle layer for about 20 minutes.
Tips:1. Add milk according to the water absorption of flour.
