Delicious.

1. Fermentation process: After the yeast powder comes into contact with the moisture and sugar in the pumpkin cake, it will start the fermentation process. During the fermentation process, yeast breaks down some of the sugar in the pumpkin pie, producing carbon dioxide and alcohol. These substances will make the pumpkin cake taste softer, and alcohols can also increase the flavor of the pumpkin cake.

2. Expansion effect: The carbon dioxide gas produced during the fermentation process will form many small holes inside the pumpkin cake, causing the pumpkin cake to expand in volume and have a softer texture.