Article in English: The butter helps to fry the bottom of the eggs quickly and maintain their shape. Make sure the butter is covering almost as much of the surface of the bottom of the pan as possible. If you don't have butter, you can use lard, olive oil, or bacon fat to make your eggs, because each will spread to coat the bottom of the pan.

Summary in Vietnamese:
Nghiêng chảo để dàn trải đều bơ trên bề mặt chảo.