Separate the egg whites from the yolks.
Add sugar to the egg whites and beat until stiff peaks form.
Mix milk and vanilla extract into the yolks.
Carefully fold the whipped egg whites into the yolk mixture.
Grease a pan with butter and place the batter over medium-low heat.
Cover with a lid and cook for 5 to 7 minutes.
Flip and cook the other side for 2 minutes.