First, prepare a proper amount of fresh purple potatoes. Purple sweet potato is rich in dietary fiber, which can not only strengthen the spleen and nourish, but also relieve constipation. This is really a very good food. First, clean the purple potato, peel it and cut it into large pieces, then steam it in cold water for about 15 minutes, and keep the heat all the time, so that every part of the purple potato can be fully heated, thus obtaining soft and waxy purple potato paste. Then take out the steamed purple potato and press it into mud, dissolve a little yeast powder with proper warm water, pour this bowl of yeast water into the air-cooled purple potato paste, and then stir.
Then add a proper amount of low-gluten flour, baking powder and white sugar into another pot, and after fully stirring, pour the stirred purple potato paste into these flour and stir it into purple potato batter. Don't add too much flour, or the steamed purple potato cake will be hard. It can be judged by the state of the batter. If the batter is sticky but easy to stir, it means that the amount of flour is right at this time.
Aft that, a layer of edible oil is brush in that cake mold, and the evenly stirred purple potato batter is poured into the mold, and production preparation can be carry out after the batter is fermented to about twice the size. Brush a thin layer of cooking oil on the surface of the batter to lock in the moisture. You can put your favorite nuts or red dates on it. After the water is boiled, put it in the cake paste and steam it for about half an hour, then simmer it for five minutes.