1. The pumpkin and purple sweet potato are steamed in a steamer, then mashed and cooled.
2. Add plain flour, water and appropriate amount of yeast powder to the purple potato puree and pumpkin puree to knead into a smooth dough.
3. Put the kneaded dough in a basin and cover with plastic wrap to ferment.
4. When the dough is fermented to 1.5 to 2 times its original size, the fermentation can be completed.
5. Take out the fermented dough and place it on the panel. Before kneading the dough, put an appropriate amount of alkaline dough on the panel, crush it with a rolling pin, and then knead it together with the dough. Knead into a smooth dough.
6. Take a small piece of each type of dough and knead it into a long strip.
7. The kneaded strips are stacked together and then rolled up. Chop it with chopsticks and turn it into a butterfly shape.
8. Add water to the steamer, put the rolled butterfly cake in the steamer and ferment for another 10 minutes, then it can be steamed.
9. Steam for 25 minutes after boiling, and the butterfly cake is done.
Tips:The dough fermented with yeast powder must be added with some alkaline noodles to prevent the steamed noodles from being sour.
