Separate egg yolk and protein.
Separate the yolk from the egg white, and refrigerate the egg white for later use.
Stir into a paste
Stir the egg yolk, milk powder and corn oil into a paste.
Add lemon juice and stir.
Take out the egg white, add lemon juice and stir until fine bubbles appear.
Add sugar three times and stir.
Add sugar in three times and continue stirring until a small sharp corner appears.
Add to egg yolk paste
Add the beaten egg whites into the yolk paste three times, stir well and put them into paper bags.
Bake for an hour.
Squeeze it on a baking tray covered with oil paper and bake it in a preheated oven for one hour, and the delicious milk powder will dissolve in the beans!