Set two small bowls on your work surface. Crack the egg gently on the side of the bowl or on the counter. It is best to get the egg to crack right in the center. Working over one of the two bowls, carefully pry the halves apart with your thumbs. Hold one half of the egg so that the yolk settles in that half. Let the egg white run over the edges and into your bowl. When this is done, drop the egg yolk into the other bowl.
The important thing is to make sure none of the egg yolk gets in with the egg white. This is not hard, just so long as you keep the yolk from breaking. If the egg white gets contaminated by egg yolk, it will not stiffen like it is supposed to when beaten with the electric mixer.