Buttercream on cake is made as follows:

Main ingredients: 4 egg whites.

Supplementary ingredients: salt, white vinegar, a spoonful of sugar.

1, 4 egg whites beaten, beaten like this (that is, egg whites have a small layer of tiny bubbles on top).

2, put a little bit of salt, a drop of white vinegar, a spoonful of sugar (spoon is ordinary small iron spoon), continue to beat the egg whites.

3, beat until a little thick (that is, it feels like you beat the egg whites like body wash foam), add another spoonful of sugar, continue to beat.

4, after that, feel than the third step in the egg white more thick when adding a spoonful of sugar, continue to beat.

5. After beating for about 10 minutes after step 4, try to pick up the egg whites you have beaten with a whisk, and if the whites can stand up, the cream is ready.