1. Knead all ingredients except yeast and butter until a thick film is formed, add yeast and butter and knead until a film is formed
2. Fermented to 1.5 times larger
3. Vent the dough and round it
4. Roll into a rectangular dough sheet with a width slightly less than the length of the toast box
5. Roll up
6. Put in toast box
7. Put it in the oven and ferment to 5 minutes full
8. When the bread is fermented, start to prepare the cake batter, divide the egg white into 3 times and add sugar, and beat until dry foaming
9. Add egg yolk
10. Stir evenly with an electric whisk
11. Sift in low-gluten flour
12. Stir evenly with a spatula
13. Corn oil and water are mixed, whipped and emulsified with an electric whisk
14. Sift in the cocoa powder
15. Stir evenly with an electric whisk
16. Pour the cocoa batter into the cake batter and mix evenly
17. Pour into the toast box with the dough
18. Shake a few times
19. Put it in the lowermost layer of the preheated oven and heat up and down at 160 degrees for 40 minutes
20. Immediately demoulding and cooling out of the oven
Tips:1. Adjust the amount of water added to the dough according to the water absorption of flour
2. Adjust the amount of sugar according to everyone's preference
3. Don't shake too hard after adding the cake batter
4. It is best to spread grease paper in the toast box for easy demoulding
5. Adjust the baking temperature according to the attributes of each person's oven
