1. Mix the oil, sugar and milk and beat until the sugar dissolves.
2. Add the egg yolk and mix well.
3. Sift in the flour and mix until there are no particles.
4. Put the egg whites into a clean, water-free and oil-free container, add sugar and beat until dry and wet foaming. (Lift the egg beater, the egg white with a small curved hook)
5. Put 1/3 of the egg whites in the egg yolk paste and stir evenly.
6. Pour it back into 2/3 of the egg whites.
7. Mix quickly and evenly.
8. Put the cake batter into a cup, 8 minutes full, exactly 12, and use a bamboo stick to make a few strokes on the cake batter to eliminate large bubbles.
9. Then it shook two or three times.
10. Put it in the preheated oven and bake at 320F/160C for 25 minutes.
11. Just let it out and let cool.
12. The cake is delicate, moist and soft.
