1. Put the egg whites into a basin without water and oil, and add a little white vinegar.
2. Put the white granulated sugar into the egg whites three times and beat until moist foaming.
3. Put the egg yolks in a large bowl, add vanilla extract, caramel syrup, milk and corn oil.
4. After mixing the egg yolks, sift in low-gluten flour.
5. Stir gently evenly.
6. Sift in the cocoa powder.
7. Continue to stir evenly.
8. Add one-third of the egg whites.
9. Stir evenly.
10. Pour the cocoa paste into the remaining egg whites.
11. Stir evenly.
12. Pour the cake batter into a 28*28 square baking pan and smooth the surface.
13. Preheat the oven and heat up and down at 170 degrees for 20-25 minutes.
14. The baked cake is upside down and let cool.
15. Spread a layer of blueberry jam (or light cream) on the cake.
16. While the cake is still warm, roll it up and shape it.
17. It can be placed in the refrigerator and set for about 1 hour.
18. Cut into pieces after setting it up~
19. Little cake, let's eat it~
20. O(∩_∩)O haha~
Tips:1. The oven settings are for reference only.
2. After the cake roll is rolled, let it cool completely, and put it in the refrigerator for 1 hour.
