1. Separate the egg white and egg yolk, add salt to the egg yolk, and stir evenly with a manual whisk.
2. Add salad oil and mix well, add milk and mix well, add a few drops of vanilla extract and mix well.
3. The banana is mashed.
4. Add the mashed banana to the egg yolk paste and mix well.
5. Sift the low-gluten flour and cocoa powder and add to the egg yolk paste.
6. Use a rubber spatula to gently stir evenly.
7. Put the egg whites in an oil-free and water-free container, first beat with an electric whisk at low speed to thick foam, then switch to medium speed, add white sugar in three times, beat until dry foaming (lift the whisk, the egg white can be pulled out A short, upright sharp corner is a dry foam).
8. Take 1/3 of the beaten egg whites and put them in the egg yolk paste, and stir evenly with a rubber spatula.
9. Pour all the mixed batter into the remaining egg whites and stir evenly.
10. Pour the batter into the mold and shake it lightly to produce large bubbles.
11. Preheat the oven at 160°C, in the lower and middle level, for about 50 minutes. After being out of the oven, let it cool down on the grill.
