The large pieces of gluten sold in the vegetable market are made of grain flour. If you want to make such gluten, you can buy cereal flour as we usually steam steamed bread with flour.

Put a proper amount of flat storage powder into a basin, dissolve yeast in warm water and stir evenly, then pour it into flat storage powder to make a uniform dough. After kneading, cover it with a wet cloth and put it in a warm place for fermentation. When the dough swells, take it out and put it on the chopping board, knead it until it is exhausted, and roll it into a thin and uniform round cake. Put it in a steamer and steam it for about half an hour on high fire. The gluten cake will rise and it will be ok if there is no water vapor on it.

These are all my practical experiences. I hope I can help you. Baidu knows to answer your questions at any time!