1. Separate the egg whites and egg yolks into a clean, oil-free and water-free basin. Add milk, corn oil, and 10 grams of fine sugar to the egg yolks, and mix them evenly with a manual whisk. Then sift in the mixed powder and stir into a delicate egg yolk paste.
2. After adding a few drops of white vinegar to the egg whites, add sugar in three times and beat until wet and foamy.
3. Take one third of the egg white and add it to the egg yolk paste.
4. Stir gently and mix evenly.
5. Then pour into the remaining two-thirds of the egg whites and stir evenly.
6. Pour the mixed cake batter into a square baking pan lined with greased paper, smooth it slightly with a spatula, squeeze the custard sauce on the surface, sprinkle a little crispy grains and coconut shreds.
7. Put it in the preheated oven and bake at 160°C for about 20 minutes until the surface is colored.
8. After the test is completed, take out the baking tray and place it on the cold shelf, tear off the greased paper on the four sides.
9. When it is warm, cover the surface with a piece of clean greased paper. After turning it over, tear off the original greased paper and apply a thin layer of whipped cream.
10. Roll it up, wrap it in oil paper and put it in the refrigerator for half an hour to set and cut into pieces.
